automation: delete code related to Python 2.7 support The building of Inno and WiX installers took a python_version argument that allowed us to specify "2" or "3" for the major Python version. Since we no longer support Python 2, we can delete this argument and everything feeding into it. Differential Revision: https://phab.mercurial-scm.org/D12264

# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil

__path__ = pkgutil.extend_path(__path__, __name__)