[SPARK-5648][SQL] support "alter ... unset tblproperties("key")"

make hivecontext support "alter ... unset tblproperties("key")"
like :
alter view viewName unset tblproperties("k")
alter table tableName unset tblproperties("k")

Author: DoingDone9 <[email protected]>

Closes #4424 from DoingDone9/unset and squashes the following commits:

6dd8bee [DoingDone9] support "alter ... unset tblproperties("key")"

(cherry picked from commit d08e7c2)
Signed-off-by: Michael Armbrust <[email protected]>

Author: pzzs

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

@@ -103,6 +103,7 @@ private[hive] object HiveQl {
     "TOK_CREATEINDEX",
     "TOK_DROPDATABASE",
     "TOK_DROPINDEX",
+    "TOK_DROPTABLE_PROPERTIES",
     "TOK_MSCK",
 
     "TOK_ALTERVIEW_ADDPARTS",
@@ -111,6 +112,7 @@ private[hive] object HiveQl {
     "TOK_ALTERVIEW_PROPERTIES",
     "TOK_ALTERVIEW_RENAME",
     "TOK_CREATEVIEW",
+    "TOK_DROPVIEW_PROPERTIES",
     "TOK_DROPVIEW",
 
     "TOK_EXPORT",