rbc: empty (and invalid) rbc-names file should give an empty name list
An empty file (if it somehow should exist) used to give a list with an empty
name. That didn't do any harm, but it was "wrong". Fix that.
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)