mbox: Don't give "Can't find next message offset" warnings when (quota) plugin accesses the message being saved.
mbox: Don't give "Can't find next message offset" warnings when (quota)
plugin accesses the message being saved.

--HG--
branch : HEAD

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