merge YARN-579 from trunk. Stop setting the Application Token in the AppMaster env, in favour of the copy present in the container token field. Contributed by Vinod Kumar Vavilapalli.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1471815 13f79535-47bb-0310-9956-ffa450edef68
merge MAPREDUCE-5181 from trunk. RMCommunicator should not use AMToken from the env. Contributed by Vinod Kumar Vavilapalli. 


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1471817 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4745. Merge 1475623 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1475625 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9357. Revert the change r1461901 to fix TestFcHdfsSymlink failures

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1475628 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-216-branch-2-gd