HDFS-6252. Phase out the old web UI in HDFS. Contributed by Haohui Mai.
HDFS-6657. Remove link to 'Legacy UI' in trunk's Namenode UI. Contributed by Vinayakumar B.
YARN-2501. Enhanced AMRMClient library to support requests against node labels. Contributed by Wangda Tan.

(cherry picked from commit a5ec3d080978a67837946a991843a081ea712539)