#468 Enabling ipv6 breaks webgui

[Csillagszemu Pityesz]

Lighttpd cannot start if ipv6 is enabled and the machine gets an address. Trying to manually start lighttpd throws a cannot bind ipv6 address error.
If someone enables ipv6 during configuration and restarts the machine - as asked by the webgui - before setting up SSH, locks oneself out remotely!
A switch would be nice to decide on what interfaces/IP addresses the webgui should be available.