Merge -c 1492958 from trunk to branch-2 to fix 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/branches/branch-2@1492959 13f79535-47bb-0310-9956-ffa450edef68
Merge -c 1492962 from trunk to branch-2 to fix MAPREDUCE-5319. Set user.name in job.xml. Contributed by Xuan Gong.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1492963 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-2' into branch-2-gd
Merge remote branch 'origin/branch-2-gd' into fb-HADOOP-9166-branch-2-gd