HIVE-6478 : SQL std auth - pass username from hiveserver2 to sessionstate (Thejas Nair, reviewed by Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1571560 13f79535-47bb-0310-9956-ffa450edef68
HIVE-5954 : SQL std auth - get_privilege_set should check role hierarchy (Thejas Nair, reviewed by Ashutosh Chauhan)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1571561 13f79535-47bb-0310-9956-ffa450edef68
HIVE-6466 : Add support for pluggable authentication modules (PAM) in Hive (Vaibhav Gumashta via Thejas Nair)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1571854 13f79535-47bb-0310-9956-ffa450edef68