Don't update maildir sync header if only sync time has changed, and that hasn't changed delayed-refresh state.
Don't update maildir sync header if only sync time has changed, and that
hasn't changed delayed-refresh state.

--HG--
branch : HEAD

jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot