HIVE-6625: HiveServer2 running in http mode should support trusted proxy access (Vaibhav Gumashta via Prasad Mujumdar)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/branch-0.13@1580023 13f79535-47bb-0310-9956-ffa450edef68