setfb not work with ipv6

[Vladislav V. Prodan]

9.0-CURRENT #0: Sun Apr 11 23:26:21 EEST 2010 amd64
net.my_fibnum: 0
net.add_addr_allfibs: 1
net.fibs: 3

# netstat -rn | grep default
default            XXX.XXX.XXX.254      UGS         0 37594940   tun1
default                           2001:5c0:1400:b::27e8         UGS 
    gif0


# setfib 1 netstat -rn | grep default
default                           2001:5c0:1400:b::27e8         UGS 
    gif0
# setfib 2 netstat -rn | grep default
default                           2001:5c0:1400:b::27e8         UGS 
    gif0

# setfib 2 route -n add -inet6 default 2001:470:27:140::1
route: writing to routing socket: File exists
add net default: gateway 2001:470:27:140::1: route already in table

# setfib 2 route -n add -inet6 default 2001:470:27:140::1
route: writing to routing socket: File exists
add net default: gateway 2001:470:27:140::1: route already in table

Change routes without setfib
# route -n change -inet6 default 2001:470:27:140::1
change net default: gateway 2001:470:27:140::1
# route -n change -inet6 default 2001:5c0:1400:b::27e8
change net default: gateway 2001:5c0:1400:b::27e8

Open PR?