[PATCH] Fix error reporting in notmuch_database_find_message_by_filename

[David Bremner]

On Sat, 17 Mar 2012 17:41:27 +0100, Justus Winter <4winter at informatik.uni-hamburg.de> wrote:
> Formerly it was possible for *message_ret to be left
> uninitialized. The documentation however clearly states that "[o]n any
> failure or when the message is not found, this function initializes
> '*message' to NULL".
> 

Pushed to 0.12