MAPREDUCE-5899. Merge change r1596931 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1596937 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10618: Merging r1596964 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1596965 13f79535-47bb-0310-9956-ffa450edef68