Yet another try at fixing APPEND.
Yet another try at fixing APPEND.

--HG--
branch : HEAD

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