Heimdal import changed kdc behaviour / broke boot

[Geoff Wing <gcw%pobox.com@localhost>]

With the new Heimdal version, kdc now has the "--detach" option
built in and does not detach by default anymore.  This causes
/etc/rc.d/kdc to hang (and thus the rest of the system startup).
This is bad.

IIRC, the last thing that changed behaviour this way (ipmon?) had
its startup flag changed in /etc/defaults/rc.conf  rather than
changing the source.  Either fix is fine by me.

Regards,
Geoff