YARN-2494. Added NodeLabels Manager internal API and implementation. Contributed by Wangda Tan.

(cherry picked from commit db7f1653198b950e89567c06898d64f6b930a0ee)
YARN-2501. Enhanced AMRMClient library to support requests against node labels. Contributed by Wangda Tan.

(cherry picked from commit a5ec3d080978a67837946a991843a081ea712539)
HADOOP-11133. Should trim the content of keystore password file for JavaKeyStoreProvider (Yi Liu via umamahesh)
(cherry picked from commit 8d7c54967d5a08cdff75a782998ee89e7537b5c4)
HADOOP-11193. Fix uninitialized variables in NativeIO.c. Contributed by Xiaoyu Yao.