Merge -c 1491989 from trunk to branch-2 to fix RN-767. Initialize application metrics at RM bootup. Contributed by Jian He.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1491990 13f79535-47bb-0310-9956-ffa450edef68
merge TEZ-731 from trunk. RPCUtil.unwrapAndThrowException should unwrap remote RuntimeExceptions. Contributed by Zhijie Shen.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1492001 13f79535-47bb-0310-9956-ffa450edef68
YARN-795. Fair scheduler queue metrics should subtract allocated vCores from available vCores. (ywskycn via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1492025 13f79535-47bb-0310-9956-ffa450edef68