mbox: Don't write garbage to mbox if message doesn't have a body.
mbox: Don't write garbage to mbox if message doesn't have a body.

--HG--
branch : HEAD

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