[PATCH] notmuch.Database.remove_message should raise exception on failure

[Justus Winter]

Quoting Daniel Kahn Gillmor (2016-02-10 17:53:46)
> The notmuch python bindings document that database.remove_message
> should raise an exception when the message removal fails, but they
> don't actually do it.

Merged, thanks!

Justus