svn merge -c 1459592 from trunk for HDFS-4584. Skip TestNNWithQJM.testNewNamenodeTakesOverWriter() on Windows.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1459593 13f79535-47bb-0310-9956-ffa450edef68