[SPARK-4529] [SQL] support view with column alias

Support view definition like

CREATE VIEW view3(valoo)
TBLPROPERTIES ("fear" = "factor")
AS SELECT upper(value) FROM src WHERE key=86;

[valoo as the alias of upper(value)]. This is missing part of SPARK-4239, for a fully view support.

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #3396 from adrian-wang/viewcolumn and squashes the following commits:

4d001d0 [Daoyuan Wang] support view with column alias

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

@@ -379,7 +379,7 @@ private[hive] object HiveQl {
   protected def nameExpressions(exprs: Seq[Expression]): Seq[NamedExpression] = {
     exprs.zipWithIndex.map {
       case (ne: NamedExpression, _) => ne
-      case (e, i) => Alias(e, s"c_$i")()
+      case (e, i) => Alias(e, s"_c$i")()
     }
   }
 

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

@@ -279,7 +279,7 @@ private[hive] case class HiveGenericUdtf(
   }
 
   override protected def makeOutput() = {
-    // Use column names when given, otherwise c_1, c_2, ... c_n.
+    // Use column names when given, otherwise _c1, _c2, ... _cn.
     if (aliasNames.size == outputDataTypes.size) {
       aliasNames.zip(outputDataTypes).map {
         case (attrName, attrDataType) =>
@@ -288,7 +288,7 @@ private[hive] case class HiveGenericUdtf(
     } else {
       outputDataTypes.zipWithIndex.map {
         case (attrDataType, i) =>
-          AttributeReference(s"c_$i", attrDataType, nullable = true)()
+          AttributeReference(s"_c$i", attrDataType, nullable = true)()
       }
     }
   }