move HDFS-4657 to branch-2.2.1

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536887 13f79535-47bb-0310-9956-ffa450edef68
YARN-1068. Add admin support for HA operations (Karthik Kambatla via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536888 13f79535-47bb-0310-9956-ffa450edef68
Fix inadvertent file changes made via r1536888 (bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536894 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5436. Move HsFtpFileSystem and HFtpFileSystem into org.apache.hdfs.web. (Contributed by Haohui Mai)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536921 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/trunk@1536982 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4311-INVESTIGATION-trunk-gd