YARN-1119. Add ClusterMetrics checks to tho TestRMNodeTransitions tests (Mit Desai via jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1521623 13f79535-47bb-0310-9956-ffa450edef68
YARN-1025. Merging change r1521670 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1521671 13f79535-47bb-0310-9956-ffa450edef68