HIVE-7392 : Support Columns Stats for Partition Columns (Ashutosh Chauhan via John Pullokkaran)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1620681 13f79535-47bb-0310-9956-ffa450edef68
HIVE-7835 : [CBO] Handle a case where FieldTimmer trims all fields from input (Ashutosh Chauhan via Harish Butani)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1620761 13f79535-47bb-0310-9956-ffa450edef68