[SPARK-6835] [SQL] Fix bug of Hive UDTF in Lateral View (ClassNotFound)

```SQL
select key, v from src lateral view stack(3, 1+1, 2+2, 3) d as v;
```
Will cause exception
```
java.lang.ClassNotFoundException: stack
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at org.apache.spark.sql.hive.HiveFunctionWrapper.createFunction(Shim13.scala:148)
at org.apache.spark.sql.hive.HiveGenericUdtf.function$lzycompute(hiveUdfs.scala:274)
at org.apache.spark.sql.hive.HiveGenericUdtf.function(hiveUdfs.scala:274)
at org.apache.spark.sql.hive.HiveGenericUdtf.outputInspector$lzycompute(hiveUdfs.scala:280)
at org.apache.spark.sql.hive.HiveGenericUdtf.outputInspector(hiveUdfs.scala:280)
at org.apache.spark.sql.hive.HiveGenericUdtf.outputDataTypes$lzycompute(hiveUdfs.scala:285)
at org.apache.spark.sql.hive.HiveGenericUdtf.outputDataTypes(hiveUdfs.scala:285)
at org.apache.spark.sql.hive.HiveGenericUdtf.makeOutput(hiveUdfs.scala:291)
at org.apache.spark.sql.catalyst.expressions.Generator.output(generators.scala:60)
at org.apache.spark.sql.catalyst.plans.logical.Generate$$anonfun$2.apply(basicOperators.scala:60)
at org.apache.spark.sql.catalyst.plans.logical.Generate$$anonfun$2.apply(basicOperators.scala:60)
at scala.Option.map(Option.scala:145)
at org.apache.spark.sql.catalyst.plans.logical.Generate.generatorOutput(basicOperators.scala:60)
at org.apache.spark.sql.catalyst.plans.logical.Generate.output(basicOperators.scala:70)
at org.apache.spark.sql.catalyst.plans.logical.LogicalPlan$$anonfun$resolveChildren$1.apply(LogicalPlan.scala:117)
at org.apache.spark.sql.catalyst.plans.logical.LogicalPlan$$anonfun$resolveChildren$1.apply(LogicalPlan.scala:117)
```

Author: Cheng Hao <hao.cheng@intel.com>

Closes #5444 from chenghao-intel/hive_udtf and squashes the following commits:

065a98c [Cheng Hao] fix bug of Hive UDTF in Lateral View (ClassNotFound)

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveQl.scala

@@ -20,6 +20,8 @@ package org.apache.spark.sql.hive
 import java.sql.Date
 
 
+import org.apache.hadoop.hive.ql.exec.{FunctionRegistry, FunctionInfo}
+
 import scala.collection.mutable.ArrayBuffer
 
 import org.apache.hadoop.hive.conf.HiveConf
@@ -1284,8 +1286,13 @@ https://cwiki.apache.org/confluence/display/Hive/Enhanced+Aggregation%2C+Cube%2C
         Explode(attributes, nodeToExpr(child))
 
       case Token("TOK_FUNCTION", Token(functionName, Nil) :: children) =>
+        val functionInfo: FunctionInfo =
+          Option(FunctionRegistry.getFunctionInfo(functionName.toLowerCase)).getOrElse(
+            sys.error(s"Couldn't find function $functionName"))
+        val functionClassName = functionInfo.getFunctionClass.getName
+
         HiveGenericUdtf(
-          new HiveFunctionWrapper(functionName),
+          new HiveFunctionWrapper(functionClassName),
           attributes,
           children.map(nodeToExpr))
 

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala

@@ -51,6 +51,12 @@ case class Order(
  * valid, but Hive currently cannot execute it.
  */
 class SQLQuerySuite extends QueryTest {
+  test("SPARK-6835: udtf in lateral view") {
+    val df = Seq((1, 1)).toDF("c1", "c2")
+    df.registerTempTable("table1")
+    val query = sql("SELECT c1, v FROM table1 LATERAL VIEW stack(3, 1, c1 + 1, c1 + 2) d AS v")
+    checkAnswer(query, Row(1, 1) :: Row(1, 2) :: Row(1, 3) :: Nil)
+  }
 
   test("SPARK-6851: Self-joined converted parquet tables") {
     val orders = Seq(