HDFS-5942. Merging change r1569124 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1569133 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5959. Merge r1569156 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1569162 13f79535-47bb-0310-9956-ffa450edef68
Branching for hadoop-2.4 releases, also set version to 2.5.0-SNAPSHOT in branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1569186 13f79535-47bb-0310-9956-ffa450edef68