head-checking: backport fix from 7d5455b988ec See 7d5455b988ec for details. Having a version in the evolve repository allow us to check the behavior when topic is enabled. It will also become the base of further head checking fix and topic compatibility.

# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)