HIVE-6800 : HiveServer2 is not passing proxy user setting through hive-site (Vaibhav Gumashta, reviewed by Prasad Mujumdar, Thejas Nair)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.13@1585214 13f79535-47bb-0310-9956-ffa450edef68