Merge 1519107. from trunk to branch-2 for YARN-771. AMRMClient support for resource blacklisting (Junping Du via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1519112 13f79535-47bb-0310-9956-ffa450edef68
YARN-1117. Improved help messages for "yarn application" and "yarn node" commands. Contributed by Xuan Gong.
svn merge --ignore-ancestry -c 1519117 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1519118 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9918. Add addIfService to CompositeService (Karthik Kambatla via Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1519130 13f79535-47bb-0310-9956-ffa450edef68