v2 _notmuch_message_ensure_metadata exception handling

[David Bremner]

Jani Nikula <jani at nikula.org> writes:

> On Sat, 25 Feb 2017, David Bremner <david at tethera.net> wrote:
>> I tried to address most of Jani's comments on v1 [1]. The bad news is
>> that the test is a bit delicate, it really does need the whole corpus.
>
> Too bad. I hope it's not too dependent on the environment and the phase
> of the Moon, etc.

We'll have to see. FWIW, the only problems I had were false positives,
i.e. passing when it should not.
>
> The series LGTM.

pushed to master