HIVE-8095 : Tez and Vectorized GROUP BY: ClassCastException: ...HiveDecimal cannot be cast to ...HiveDecimalWritable (Matt McCline via Jitendra Nath Pandey)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1625217 13f79535-47bb-0310-9956-ffa450edef68