svn merge -c 1464548 Merging from trunk to branch-2 to fix HDFS-4548.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1464553 13f79535-47bb-0310-9956-ffa450edef68
Porting fix for MAPREDUCE-5083 to 2.0.4-alpha. MiniMRCluster should use a random component when creating an actual cluster. Contributed by Siddharth Seth.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1464634 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-YARN-474-branch-2-gd