rhg: centralize index header parsing
Centralize index header parsing, parse the generaldelta flag,
and leave breadcrumbs to relate the code to python.
Differential Revision: https://phab.mercurial-scm.org/D11881
# __init__.py - Startup and module loading logic for Mercurial.
#
# Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
# Allow 'from mercurial import demandimport' to keep working.
import hgdemandimport
demandimport = hgdemandimport