YARN-1811. Fixed AMFilters in YARN to correctly accept requests from either web-app proxy or the RMs when HA is enabled. Contributed by Robert Kanter.
svn merge --ignore-ancestry -c 1579877 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1579878 13f79535-47bb-0310-9956-ffa450edef68