HADOOP-9624. Merging change r1494363 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1494365 13f79535-47bb-0310-9956-ffa450edef68
YARN-694. Starting to use NMTokens to authenticate all communication with NodeManagers. Contributed by Omkar Vinit Joshi.
svn merge --ignore-ancestry -c 1494369 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1494370 13f79535-47bb-0310-9956-ffa450edef68
merge YARN-848 from trunk. Fix NodeManager to register with RM using the fully qualified hostname. Contributed by Hitesh Shah.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1494389 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-MAPREDUCE-4884-branch-2-gd