mail/mlmmj: handle X-Original-From

when used in conjonction with rspamd like on the FreeBSD mailing lists
setup, rspamd will handle the munge of the from in case of sender of
email with strong DMARC policy (yahoo, google), rspamd will set the
X-Original-From field with the original email address, use it to check
if the sender is a member of the list it is sending email to