move HDFS-4657 to branch-2.2.1

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1536886 13f79535-47bb-0310-9956-ffa450edef68
Merge r1536888 from trunk to branch-2 for YARN-1068. Add admin support for HA operations (Karthik Kambatla via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1536899 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5436. Merging change r1536921 from trunk to branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1536922 13f79535-47bb-0310-9956-ffa450edef68
YARN-1306. Clean up hadoop-sls sample-conf according to YARN-1228 (Wei Yan via Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1536990 13f79535-47bb-0310-9956-ffa450edef68