YARN-895. Changed RM state-store to not crash immediately if RM restarts while the state-store is down. Contributed by Jian He.
svn merge --ignore-ancestry -c 1547538 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1547539 13f79535-47bb-0310-9956-ffa450edef68