Make name node listen to all interfaces.

Change dfs.namenode.rpc-bind-host and dfs.namenode.servicerpc-bind-host to
"0.0.0.0" so that namenode RPC (client and HDFS services)
will be listening to all interfaces.
Merge pull request #1 from Dictanova/bind_namenode_to_all_interfaces

Make namenode listen to all interfaces.