[Dovecot] Migration from Courier to dovecot

[Werner Detter]

> The conversion of the Mailbox from Courier to Dovecot will be done with
> "courier-dovecot-migrate.pl"-script[1], which works fine. However after
> running "courier-dovecot-migrate.pl" the Courier-Files still remain in
> the Maildir.

expressed unlucky :-)

sure, dovecot doesn't need these files after the migration. I have to
test, if it's possible to convert from a previously "courier to
dovecot migrated maildir" back to courier-format.