HDFS-5690. Merge change r1553167 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1553168 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10175. Merging change r1553169 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1553171 13f79535-47bb-0310-9956-ffa450edef68