ipfw dscp support

[alan yang]

>
> reading ipfw-classifyd divert socket sendto() with packet sin_port set
> to flow->if_fwrule (ftp == 1000 for instance), was expecting ipfw
> would continue with next rule which is 1010 in above.  But ipfw seems
> to have continue with matching rule 500.
>
with further looking, divert and ipfw rule processing work as
documented in man page.

sorry about above confusion.