hgext3rd/__init__.py

hg: don't attempt to extend `sys.path` with the user site without `APPDATA`

This variable is created by the system and *should* be available, but
test-lfs-bundle.t has a test where it is explicitly unset.  It wasn't caught
before because prior to 95af358fcdfe, it was limited to the py2exe binary.  As a
precaution, fix both that and the pyoxidizer case that was causing the test to
fail.

Differential Revision: https://phab.mercurial-scm.org/D11354

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

__path__ = pkgutil.extend_path(__path__, __name__)