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.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1487175 13f79535-47bb-0310-9956-ffa450edef68