IPv6 fixes
IPv6 fixes

Iocage doesn't do the right thing when configuring IPv6, this small patch addresses this.

A vnet jail with the following configuration now works

ip6_addr:vnet0|xxxx:xxxx:xxxx:xxxx::xxx/64
notdavidcronenberg/iocage,sineer/iocage,dlangille/iocage,lattera/iocage,moviuro/iocage,freqlabs/iocage,sineer/iocage,skunkwerks/iocage,sineer/iocage,vtalk/iocage,Hivlaher/iocage,skoef/iocage