HADOOP-10495. Merging change r1587137 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1587138 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10496. Merging change r1587141 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1587144 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6237. Merging change r1587146 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1587147 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6238. Merging change r1587148 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1587150 13f79535-47bb-0310-9956-ffa450edef68