split: remove an unnecessary (and confusingly typed) fallback revision
`opts.get('rev') or '.'` is either a list of strings or just a
string. It happened to work because `'.'[0] == '.'` on Python 2, but
it won't work on Python 3 (for byte strings). The fallback value
wasn't even needed (it was also set just after), so let's just remove
it.
This software was downloaded from
https://www.mercurial-scm.org/repo/evolve/
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'.