HIVE-7540 - NotSerializableException encountered when using sortByKey transformation (Rui Li via Brock) [Spark Branch]

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1617202 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'upstream/spark' into spark
Merge remote branch 'origin/spark' into HIVE-7624