If mbox headers have CRLF linefeeds, handle them properly instead of corrupting the headers.
If mbox headers have CRLF linefeeds, handle them properly instead of
corrupting the headers.

--HG--
branch : HEAD

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