RBF: Choose to enable the default nameservice to read/write files

The default nameservice can provide some default properties for the namenode protocol. And if we cannot find the path, we will get a location in default nameservice. From my side as cluster administrator, we need all files to be written in the location from the MountTableEntry. If no responding location, some error will return. It is not better to happen some files are written in some unknown location. We should provide a specific parameter to enable the default nameservice to store files.