[SPARK-15396][SQL][DOC] It can't connect hive metastore database

#### What changes were proposed in this pull request?
The `hive.metastore.warehouse.dir` property in hive-site.xml is deprecated since Spark 2.0.0. Users might not be able to connect to the existing metastore if they do not use the new conf parameter `spark.sql.warehouse.dir`.

This PR is to update the document and example for explaining the latest changes in the configuration of default location of database.

Below is the screenshot of the latest generated docs:

<img width="681" alt="screenshot 2016-05-20 08 38 10" src="https://cloud.githubusercontent.com/assets/11567269/15433296/a05c4ace-1e66-11e6-8d2b-73682b32e9c2.png">

<img width="789" alt="screenshot 2016-05-20 08 53 26" src="https://cloud.githubusercontent.com/assets/11567269/15433734/645dc42e-1e68-11e6-9476-effc9f8721bb.png">

<img width="789" alt="screenshot 2016-05-20 08 53 37" src="https://cloud.githubusercontent.com/assets/11567269/15433738/68569f92-1e68-11e6-83d3-ef5bb221a8d8.png">

No change is made in the R's example.

<img width="860" alt="screenshot 2016-05-20 08 54 38" src="https://cloud.githubusercontent.com/assets/11567269/15433779/965b8312-1e68-11e6-8bc4-53c88ceacde2.png">

#### How was this patch tested?
N/A

Author: gatorsmile <gatorsmile@gmail.com>

Closes #13225 from gatorsmile/document.

docs/sql-programming-guide.md

@@ -1663,43 +1663,50 @@ Configuration of Hive is done by placing your `hive-site.xml`, `core-site.xml` (
 
 <div data-lang="scala"  markdown="1">
 
-When working with Hive one must construct a `HiveContext`, which inherits from `SQLContext`, and
-adds support for finding tables in the MetaStore and writing queries using HiveQL. Users who do
-not have an existing Hive deployment can still create a `HiveContext`. When not configured by the
-hive-site.xml, the context automatically creates `metastore_db` in the current directory and
-creates `warehouse` directory indicated by HiveConf, which defaults to `/user/hive/warehouse`.
-Note that you may need to grant write privilege on `/user/hive/warehouse` to the user who starts
-the spark application.
+When working with Hive, one must instantiate `SparkSession` with Hive support, including
+connectivity to a persistent Hive metastore, support for Hive serdes, and Hive user-defined functions.
+Users who do not have an existing Hive deployment can still enable Hive support. When not configured
+by the `hive-site.xml`, the context automatically creates `metastore_db` in the current directory and
+creates a directory configured by `spark.sql.warehouse.dir`, which defaults to the directory
+`spark-warehouse` in the current directory that the spark application is started. Note that 
+the `hive.metastore.warehouse.dir` property in `hive-site.xml` is deprecated since Spark 2.0.0.
+Instead, use `spark.sql.warehouse.dir` to specify the default location of database in warehouse.
+You may need to grant write privilege to the user who starts the spark application.
 
 {% highlight scala %}
-// sc is an existing SparkContext.
-val sqlContext = new org.apache.spark.sql.hive.HiveContext(sc)
+// warehouse_location points to the default location for managed databases and tables
+val conf = new SparkConf().setAppName("HiveFromSpark").set("spark.sql.warehouse.dir", warehouse_location)
+val spark = SparkSession.builder.config(conf).enableHiveSupport().getOrCreate()
 
-sqlContext.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)")
-sqlContext.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src")
+spark.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)")
+spark.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src")
 
 // Queries are expressed in HiveQL
-sqlContext.sql("FROM src SELECT key, value").collect().foreach(println)
+spark.sql("FROM src SELECT key, value").collect().foreach(println)
 {% endhighlight %}
 
 </div>
 
 <div data-lang="java"  markdown="1">
 
-When working with Hive one must construct a `HiveContext`, which inherits from `SQLContext`, and
-adds support for finding tables in the MetaStore and writing queries using HiveQL. In addition to
-the `sql` method a `HiveContext` also provides an `hql` method, which allows queries to be
-expressed in HiveQL.
+When working with Hive, one must instantiate `SparkSession` with Hive support, including
+connectivity to a persistent Hive metastore, support for Hive serdes, and Hive user-defined functions.
+Users who do not have an existing Hive deployment can still enable Hive support. When not configured
+by the `hive-site.xml`, the context automatically creates `metastore_db` in the current directory and
+creates a directory configured by `spark.sql.warehouse.dir`, which defaults to the directory
+`spark-warehouse` in the current directory that the spark application is started. Note that 
+the `hive.metastore.warehouse.dir` property in `hive-site.xml` is deprecated since Spark 2.0.0.
+Instead, use `spark.sql.warehouse.dir` to specify the default location of database in warehouse.
+You may need to grant write privilege to the user who starts the spark application.
 
 {% highlight java %}
-// sc is an existing JavaSparkContext.
-HiveContext sqlContext = new org.apache.spark.sql.hive.HiveContext(sc.sc);
+SparkSession spark = SparkSession.builder().appName("JavaSparkSQL").getOrCreate();
 
-sqlContext.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)");
-sqlContext.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src");
+spark.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)");
+spark.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src");
 
 // Queries are expressed in HiveQL.
-Row[] results = sqlContext.sql("FROM src SELECT key, value").collect();
+Row[] results = spark.sql("FROM src SELECT key, value").collect();
 
 {% endhighlight %}
 
@@ -1707,18 +1714,25 @@ Row[] results = sqlContext.sql("FROM src SELECT key, value").collect();
 
 <div data-lang="python"  markdown="1">
 
-When working with Hive one must construct a `HiveContext`, which inherits from `SQLContext`, and
-adds support for finding tables in the MetaStore and writing queries using HiveQL.
+When working with Hive, one must instantiate `SparkSession` with Hive support, including
+connectivity to a persistent Hive metastore, support for Hive serdes, and Hive user-defined functions.
+Users who do not have an existing Hive deployment can still enable Hive support. When not configured
+by the `hive-site.xml`, the context automatically creates `metastore_db` in the current directory and
+creates a directory configured by `spark.sql.warehouse.dir`, which defaults to the directory
+`spark-warehouse` in the current directory that the spark application is started. Note that 
+the `hive.metastore.warehouse.dir` property in `hive-site.xml` is deprecated since Spark 2.0.0.
+Instead, use `spark.sql.warehouse.dir` to specify the default location of database in warehouse.
+You may need to grant write privilege to the user who starts the spark application.
+
 {% highlight python %}
-# sc is an existing SparkContext.
-from pyspark.sql import HiveContext
-sqlContext = HiveContext(sc)
+from pyspark.sql import SparkSession
+spark = SparkSession.builder.enableHiveSupport().getOrCreate()
 
-sqlContext.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)")
-sqlContext.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src")
+spark.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)")
+spark.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src")
 
 # Queries can be expressed in HiveQL.
-results = sqlContext.sql("FROM src SELECT key, value").collect()
+results = spark.sql("FROM src SELECT key, value").collect()
 
 {% endhighlight %}
 

examples/src/main/scala/org/apache/spark/examples/sql/hive/HiveFromSpark.scala

@@ -37,10 +37,13 @@ object HiveFromSpark {
   def main(args: Array[String]) {
     val sparkConf = new SparkConf().setAppName("HiveFromSpark")
 
-    // A hive context adds support for finding tables in the MetaStore and writing queries
-    // using HiveQL. Users who do not have an existing Hive deployment can still create a
-    // HiveContext. When not configured by the hive-site.xml, the context automatically
-    // creates metastore_db and warehouse in the current directory.
+    // When working with Hive, one must instantiate `SparkSession` with Hive support, including
+    // connectivity to a persistent Hive metastore, support for Hive serdes, and Hive user-defined
+    // functions. Users who do not have an existing Hive deployment can still enable Hive support.
+    // When not configured by the hive-site.xml, the context automatically creates `metastore_db`
+    // in the current directory and creates a directory configured by `spark.sql.warehouse.dir`,
+    // which defaults to the directory `spark-warehouse` in the current directory that the spark
+    // application is started.
     val spark = SparkSession.builder
       .config(sparkConf)
       .enableHiveSupport()