HADOOP-9935. Revert from branch-2.1-beta.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1523833 13f79535-47bb-0310-9956-ffa450edef68
YARN-1001. Added a web-service to get statistics about per application-type per state for consumption by downstream projects. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1523855 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1523857 13f79535-47bb-0310-9956-ffa450edef68
YARN-1184. ClassCastException during preemption enforcement.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1523865 13f79535-47bb-0310-9956-ffa450edef68