Log Message:
notmuch: update to 0.25.3.

Notmuch 0.25.3 (2017-12-08)
===========================

Emacs
-----

Extend mitigation (disabling handling x-display in text/enriched) for
Emacs bug #28350 to Emacs versions before 24.4 (i.e. without
`advice-add`).

Command Line Interface
----------------------

Correctly report userid validity. Fix test suite failure for GMime >=
3.0.3. This change raises the minimum supported version of GMime 3.x
to 3.0.3.