HDFS-6153. Document "fileId" and "childrenNum" fields in the FileStatus Json schema

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1588258 13f79535-47bb-0310-9956-ffa450edef68
YARN-1931. Private API change in YARN-1824 in 2.4 broke compatibility with previous releases (Sandy Ryza via tgraves)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1588281 13f79535-47bb-0310-9956-ffa450edef68