HIVE-6782 : HiveServer2Concurrency issue when running with tez intermittently, throwing org.apache.tez.dag.api.SessionNotRunning: Application not running error (Vikram Dixit K, reviewed by Thejas Nair)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1585810 13f79535-47bb-0310-9956-ffa450edef68