MAPREDUCE-5237. Add methods that were removed from ClusterStatus back into 2.x so as to be compatible with 1.x. Contributed by Zhijie Shen.
Incompatible as ClusterStatus.UNINITIALIZED_MEMORY_VALUE is a long now and so breaks 0.23.x but it shouldn't be a big deal in reality.
svn merge --ignore-ancestry -c 1487175 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1487176 13f79535-47bb-0310-9956-ffa450edef68
YARN-422. Add a NM Client library to help application-writers. Contributed by Zhijie Shen.
svn merge --ignore-ancestry -c 1487184 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1487187 13f79535-47bb-0310-9956-ffa450edef68