windows: use abspath in subrepo
We replace `os.path.abspath` with `util.abspath`. This should solve more "drive
capitalization" issue on Windows.
Differential Revision: https://phab.mercurial-scm.org/D11065
# name space package to host third party extensionsfrom __future__ import absolute_importimport pkgutil__path__ = pkgutil.extend_path(__path__, __name__)