Ensure default route is set separately for IPv4 and IPv6

{code}
root@freenas-pmh[~]# uname -a
FreeBSD freenas-pmh.local 11.3-RELEASE FreeBSD 11.3-RELEASE #0 r325575+1fc67f7a521(HEAD): Mon Nov  4 19:43:55 UTC 2019     root@nemesis:/freenas-releng-beta/freenas/_BE/objs/freenas-releng-beta/freenas/_BE/os/sys/FreeNAS.amd64  amd64
root@freenas-pmh[~]# iocage list -h
1    cloud    up    11.2-RELEASE    217.29.46.105
2    gateway    up    11.2-RELEASE    217.29.46.102
3    gitea    up    11.2-RELEASE    217.29.46.111
4    guacamole    up    11.2-RELEASE    217.29.46.108
5    mineos    up    11.2-RELEASE    217.29.46.103
root@freenas-pmh[~]# iocage get ip4_addr cloud
vnet0|217.29.46.105/26
root@freenas-pmh[~]# iocage get defaultrouter cloud
217.29.46.97
root@freenas-pmh[~]# iocage console cloud
Last login: Wed Nov  6 13:32:40 on pts/4
FreeBSD 11.3-RELEASE (FreeNAS.amd64) #0 r325575+1fc67f7a521(HEAD): Mon Nov  4 19:43:55 UTC 2019

Welcome to FreeBSD!
[...]
root@cloud:~ # netstat -rn4
Routing tables

Internet:
Destination        Gateway            Flags     Netif Expire
127.0.0.1          link#1             UH          lo0
217.29.46.64/26    link#2             U       epair0b
217.29.46.105      link#2             UHS         lo0
{code}