fix for dump headers

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:

> On Tue, Mar 28 2017, David Bremner <david at tethera.net> wrote:
>
>> When I added message properties to the dump output I messed up the
>> copy-paste to add properties to the header. The fix is trivial, but
>> I'm not sure if this means we should bump the format version
>> (i.e. write #notmuch-dump:3) to denote the header can be relied
>> upon. I guess it doesn't hurt to do so. Opinions?
>
> I'd say bump the format version... so rest of the series LGTM.
>
> Tomi

OK, pushed to master and release

d