HADOOP-9294. Merge 1444415 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1444416 13f79535-47bb-0310-9956-ffa450edef68
Revering r1444416 because it committed unnecessary changes.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1444418 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9294. Merge 1444415 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1444419 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4470. Merging change r1443744 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1444430 13f79535-47bb-0310-9956-ffa450edef68