svn merge -c 1503957 FIXES: MAPREDUCE-5380. Invalid mapred command should return non-zero exit code. Contributed by Stephen Chu


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1503959 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4998. TestUnderReplicatedBlocks fails intermittently. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1503975 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.23' into branch-0.23-gd
Merge remote branch 'origin/branch-0.23-gd' into fb-xxx-hadoop-auth-kerberos-realm-branch-0.23-gd