changegroup: pass function to resolve delta parents into constructor
Previously, _deltaparent() encapsulated the logic for all 3
delta parent modes of operation. The choice of delta parent
is static for the lifetime of the packer and can be passed into
the packer as a callable. So do that.
Differential Revision: https://phab.mercurial-scm.org/D4132
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)