YARN-1121. Changed ResourceManager's state-store to drain all events on shut-down. Contributed by Jian He.
svn merge --ignore-ancestry -c 1540232 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1540233 13f79535-47bb-0310-9956-ffa450edef68