HDFS-6131. Move HDFSHighAvailabilityWithNFS.apt.vm and HDFSHighAvailabilityWithQJM.apt.vm from Yarn to HDFS. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1579736 13f79535-47bb-0310-9956-ffa450edef68