HDFS-4626. ClientProtocol#getLinkTarget should throw an exception for non-symlink and non-existent paths.  (Andrew Wang via cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493987 13f79535-47bb-0310-9956-ffa450edef68
merge YARN-805 from trunk. Fix javadoc and annotations on classes in the yarn-api package. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1493993 13f79535-47bb-0310-9956-ffa450edef68
YARN-834. Fixed annotations for yarn-client module, reorganized packages and clearly differentiated *Async apis. Contributed by Arun C Murthy and Zhijie Shen.
svn merge --ignore-ancestry -c 1494017 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1494018 13f79535-47bb-0310-9956-ffa450edef68