obscache: extract code to update from new revision
Code cleanup and prepare upstreaming. The make the code more likely to work with
the key validation returning an iterator of revs to update the cache with.
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'.