svn merge -c 1482121. Merging from trunk to branch-2 to fix HDFS-4805.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1482122 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5220. Setter methods in TaskCompletionEvent are public in MR1 and protected in MR2. (sandyr via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1482143 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5240. Fix a bug in MRAppMaster because of which OutputCommitter could not access credentials set by the user. Contributed by Vinod Kumar Vavilapalli.
svn merge --ignore-ancestry -c 1482175 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1482176 13f79535-47bb-0310-9956-ffa450edef68