[PATCH] python: Fix database.add_message

[David Bremner]

Dylan Baker <dylan at pnwbakers.com> writes:

> b10ce6bc23002d48916b1b2f375480e7540e3164 introduced a new index_file
> method as a replacement for add_message. It helpfully made add_message
> an alias for index_file, unfortunately it got the signature wrong by
> explicitly passing self as an argument.
>
> cc: Daniel Kahn Gillmor <dkg at fifthhorseman.net>

Thanks. We have another version that I was about to commit

https://www.mail-archive.com/notmuch@notmuchmail.org/msg45038.html

The only difference is that Gaute (more or less by request) added a
deprecation warning.  I don't really know how warnings in python work,
does that sound sensible?

d