HADOOP-9323. Merge change 1449977 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1449979 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4235. When outputting XML, OfflineEditsViewer can't handle some edits containing non-ASCII strings. Contributed by Colin Patrick McCabe.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1449985 13f79535-47bb-0310-9956-ffa450edef68
YARN-390. Merge r1449980 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1449986 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-7487. DF should throw a more reasonable exception when mount cannot be determined. Contributed by Andrew Wang.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1449994 13f79535-47bb-0310-9956-ffa450edef68