HDFS-5004. Add additional JMX bean for NameNode status data. Contributed by Trevor Lorimer.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1507534 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5035.  getFileLinkStatus and rename do not correctly check permissions of symlinks (Andrew Wang via Colin Patrick McCabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1507535 13f79535-47bb-0310-9956-ffa450edef68