HDFS-6190. Merge r1584376 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1584377 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5818. Added "hsadmin" command into mapred.cmd. Contributed by Jian He.
svn merge --ignore-ancestry -c 1584378 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1584380 13f79535-47bb-0310-9956-ffa450edef68