HDFS-4693. Merge 1468457 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1468469 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5015. Coverage fix for org.apache.hadoop.mapreduce.tools.CLI (Aleksey Gorshkov via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1468484 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-YAHOO-271-branch-2-gd