MAPREDUCE-5355. Merging change r1499149 from branch-2 to branch-2.1-beta.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1499151 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5359. Merging change r1499154 from branch-2 to branch-2.1-beta.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1499157 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9509. Merging change r1499156 from branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1499165 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9515. Merging change r1499167 from branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1499169 13f79535-47bb-0310-9956-ffa450edef68