YARN-1098. Separate out RM services into Always On and Active (Karthik Kambatla via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1521560 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5020. Compile failure with JDK8 (Trevor Robinson via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1521576 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5085. Refactor o.a.h.nfs to support different types of authentications. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1521601 13f79535-47bb-0310-9956-ffa450edef68
YARN-1119. Add ClusterMetrics checks to tho TestRMNodeTransitions tests (Mit Desai via jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1521611 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch: upstream/trunk