YARN-410. Fixed RM UI so that the new lines diagnostics for a failed app on the per-application page are translated to html line breaks. Contributed by Omkar Vinit Joshi


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1453638 13f79535-47bb-0310-9956-ffa450edef68