Merge -r 1430362:1430363 from trunk to branch-2. Fixes: MAPREDUCE-4278. Cannot run two local jobs in parallel from the same gateway. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1430369 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9119. Merge 1430387 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1430389 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-4899 fix branch-2 merge issue in pom

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1430470 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4100. Fix all findbug security warings. Contributed by Liang Xie


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1430545 13f79535-47bb-0310-9956-ffa450edef68