[PATCH 0/5] Fix notmuch_database_get_directory API

[Austin Clements]

This is a proposed last-minute change for 0.13.  It fixes the
notmuch_database_get_directory API in the same way we're fixing
notmuch_database_open, etc in this release.  Since this is a
backwards-incompatible change, it would be nice to lump it with the
other API-breaking changes.

To keep the patch simple, this does not change the behavior of
notmuch_database_get_directory, but it puts us in a good position to
fix it in the future.