obshashrange: use the dualsourcecache as a base for the cache
This will easily open the way to incrementally updated obshashrange cache.
Small update are needed to the data base schema so be bump the version
Currently the update function is not warming the cache (but details case where
it is invalidated).
This software was downloaded from
http://hg.netv6.net/evolve-main/
Copyright 2011 Peter Arrenbrecht <peter.arrenbrecht@gmail.com>
Logilab SA <contact@logilab.fr>
Pierre-Yves David <pierre-yves.david@ens-lyon.org>
Patrick Mezard <patrick@mezard.eu>
This software may be used and distributed according to the terms of the GNU
General Public License version 2 or any later version.
On Debian systems, the complete text of the GNU General Public License version
2 can be found in `/usr/share/common-licenses/GPL-2'.