HADOOP-9289. Merge 1443108 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1443127 13f79535-47bb-0310-9956-ffa450edef68
merge YARN-355 from trunk. Fixes a bug where RM app submission could jam under load. Contributed by Daryn Sharp.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1443134 13f79535-47bb-0310-9956-ffa450edef68
Release Notes for hadoop-2.0.3-alpha.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1443151 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-4977. Documentation for pluggable shuffle and pluggable sort. (tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1443170 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'branch-2' of github.com:griddynamics/yhadoop-common into branch-2-gd
Merge branch 'branch-2-gd' of github.com:griddynamics/yhadoop-common into fb-MAPREDUCE-4884-branch-2-gd