HIVE-8284 : Equality comparison is done between two floating point variables in HiveRelMdUniqueKeys#getUniqueKeys() (JongWon Park via Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1639252 13f79535-47bb-0310-9956-ffa450edef68