YARN-812. Set default logger for application summary logger to hadoop.root.logger. Contributed by Siddarth Seth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1492958 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5319. Set user.name in job.xml. Contributed by Xuan Gong.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1492962 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4310-trunk-gd