YARN-1368. Added core functionality of recovering container state into schedulers after ResourceManager Restart so as to preserve running work in the cluster. Contributed by Jian He.
svn merge --ignore-ancestry -c 1601303 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1601304 13f79535-47bb-0310-9956-ffa450edef68