Don't Warn when there's old backup to delete

[Sylvain Beucler]

duplicity uses a Warn logging, that output on stderr, when there's no old backup to delete.
http://bazaar.launchpad.net/~duplicity-team/duplicity/0.7-series/annotate/head%3A/duplicity-bin#L776

I'd like to use it in a cron job, and only get stderr (that is error and no just notices) sent by mail:
0 20 * * * duplicity --something > /dev/null
(I'm actually using the "duply" wrapper but it's the same thing)

With warn, I get a mail from Cron everyday because of this Warn.
I'd like to receive a mail from Cron only when something important happened to the backup, something that requires my sysadmin time. In this case it's perfectly normal, it's just that there's nothing to remove yet, I don't have to do anything.

I suggest moving it to Notice or another value that doesn't go to stderr.

The current workaround is to use verbosity=1 (which you do not recommend :)).