HDFS-4635. Move BlockManager#computeCapacity to LightWeightGSet. Contributed by Suresh Srinivas.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1461364 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9194. RPC Support for QoS. (Junping Du via llu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1461370 13f79535-47bb-0310-9956-ffa450edef68