YARN-2269. Remove external links from YARN UI. Contributed by Craig Welch


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609591 13f79535-47bb-0310-9956-ffa450edef68
Merge r1609594 from trunk. Moved few YARN entries in CHANGES.txt from 2.5 to 2.6

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1609595 13f79535-47bb-0310-9956-ffa450edef68