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
MAPREDUCE-5497. Changed MRAppMaster to sleep only after doing everything else but just before ClientService to avoid race conditions during RM restart. Contributed by Jian He.
svn merge --ignore-ancestry -c 1521699 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1521700 13f79535-47bb-0310-9956-ffa450edef68