HIVE-6799: HiveServer2 needs to map kerberos name to local name before proxy check (Dilli Arumugam reviewed by Vaibhav Gumashta)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.14@1629117 13f79535-47bb-0310-9956-ffa450edef68