rust-chg: send client-side environment variables to server
This is also needed to run config validation.
The "validate" request and its response handling will be implemented in
the next batch.
Differential Revision: https://phab.mercurial-scm.org/D8364
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)