Merge r1608334 from trunk. YARN-1367. Changed NM to not kill containers on NM resync if RM work-preserving restart is enabled. Contributed by Anubhav Dhoot

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1608336 13f79535-47bb-0310-9956-ffa450edef68