HIVE-6864 : HiveServer2 concurrency uses incorrect user information in unsecured mode (Vaibhav Gumashta via Thejas Nair)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.13@1586493 13f79535-47bb-0310-9956-ffa450edef68