HIVE-5771 : Constant propagation optimizer for Hive (Ted Xu via Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1613661 13f79535-47bb-0310-9956-ffa450edef68
HIVE-7514 : Vectorization does not handle constant expression whose value is NULL (Hari Sankar via Jitendra Nath Pandey)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1613663 13f79535-47bb-0310-9956-ffa450edef68