YARN-2735. diskUtilizationPercentageCutoff and diskUtilizationSpaceCutoff are initialized twice in DirectoryCollection. (Zhihai Xu via kasha)

(cherry picked from commit 061bc293c8dd3e2605cf150568988bde18407af6)
HDFS-7381. Decouple the management of block id and gen stamps from FSNamesystem. Contributed by Haohui Mai.
YARN-2843. Fixed NodeLabelsManager to trim inputs for hosts and labels so as to make them work correctly. Contributed by Wangda Tan.

(cherry picked from commit 0fd97f9c1989a793b882e6678285607472a3f75a)