HDFS-6849. Replace HttpFS custom proxyuser handling with common implementation. (tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1617831 13f79535-47bb-0310-9956-ffa450edef68
YARN-2277. Added cross-origin support for the timeline server web services. Contributed by Jonathan Eagles.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1617832 13f79535-47bb-0310-9956-ffa450edef68
YARN-2070. Made DistributedShell publish the short user name to the timeline server. Contributed by Robert Kanter.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1617837 13f79535-47bb-0310-9956-ffa450edef68