HDFS-6028. Merging change r1572753 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1572758 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10374. Merging r1572783 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1572784 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5665. Add audience annotations to MiniMRYarnCluster and MiniMRCluster. (Anubhav Dhoot via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1572796 13f79535-47bb-0310-9956-ffa450edef68