HIVE-7474: Expression Converter needs to handle Flattened expressions (Laljo John Pullokkaran via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1612713 13f79535-47bb-0310-9956-ffa450edef68
HIVE-7478: CBO: PPD push conditions to Join Operators (Harish Butani via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1612744 13f79535-47bb-0310-9956-ffa450edef68