YARN-1357. Merging change r1537296 from branch-2 to branch-2.2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1537298 13f79535-47bb-0310-9956-ffa450edef68
YARN-1358. Merging change r1537307 from branch-2 to branch-2.2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1537309 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5065. Merging change r1512871 and r1537320 from branch-2 to branch-2.2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1537326 13f79535-47bb-0310-9956-ffa450edef68
YARN-1321. Changed NMTokenCache to support both singleton and an instance usage. Contributed by Alejandro Abdelnur.
svn merge --ignore-ancestry -c 1537334 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.2@1537336 13f79535-47bb-0310-9956-ffa450edef68