[SPARK-7084] improve saveAsTable documentation

Author: madhukar <phatak.dev@gmail.com>

Closes #5654 from phatak-dev/master and squashes the following commits:

386f407 [madhukar] #5654 updated for all the methods
2c997c5 [madhukar] Merge branch 'master' of https://github.com/apache/spark
00bc819 [madhukar] Merge branch 'master' of https://github.com/apache/spark
2a802c6 [madhukar] #5654 updated the doc according to comments
866e8df [madhukar] [SPARK-7084] improve saveAsTable documentation

sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala

@@ -1192,6 +1192,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental
@@ -1208,6 +1211,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental
@@ -1232,6 +1238,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental
@@ -1248,6 +1257,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental
@@ -1264,6 +1276,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental
@@ -1285,6 +1300,9 @@ class DataFrame private[sql](
    * there is no notion of a persisted catalog in a standard SQL context.  Instead you can write
    * an RDD out to a parquet file, and then register that file as a table.  This "table" can then
    * be the target of an `insertInto`.
+   *
+   * Also note that while this function can persist the table metadata into Hive's metastore,
+   * the table will NOT be accessible from Hive.
    * @group output
    */
   @Experimental