HDFS-5128. Allow multiple net interfaces to be used with HA namenode RPC server. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1517982 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1517989 merging from trunk to branch-2 to fix HDFS-5132.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1517990 13f79535-47bb-0310-9956-ffa450edef68
Adding the new test file for HDFS-3245 that was accidentally dropped

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1517995 13f79535-47bb-0310-9956-ffa450edef68