YARN-1374. Changed ResourceManager to start the preemption policy monitors as active services. Contributed by Karthik Kambatla.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1539089 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5458. Datanode failed volume threshold ignored if exception is thrown in getDataDirsFromURIs. Contributed by Mike Mellenthin.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1539091 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HDFS-4312-trunk-gd