IPv6 firewall

```
What steps will reproduce the problem?
1. In the GUI, click on a node then click on "services", then look
under the "Security" menu and click on Firewall
2. In the Firewall configuration file, it would be nice to have
configurations for IPv6 firewall as well as IPv4
3.

What is the expected output? What do you see instead?

Currently only includes configurations for IPv4 firewall.

What version of the product are you using? On what operating system?

Latest SVN bits as of 05/31/2013, on ubuntu 12.04

Please provide any additional information below.

Example configuration lines:

# IPv6 stateful packet filter
/sbin/ip6tables -F
/sbin/ip6tables -X
/sbin/ip6tables -A OUTPUT -o eth1 -j ACCEPT
/sbin/ip6tables -A INPUT -i eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
/sbin/ip6tables -A INPUT -i eth0 -j ACCEPT
/sbin/ip6tables -A OUTPUT -o eth0 -j ACCEPT
/sbin/ip6tables -A INPUT -s fe80::/10 -j ACCEPT
/sbin/ip6tables -A OUTPUT -s fe80::/10 -j ACCEPT
/sbin/ip6tables -I INPUT -p icmpv6 -j ACCEPT
/sbin/ip6tables -I OUTPUT -p icmpv6 -j ACCEPT
/sbin/ip6tables -I FORWARD -p icmpv6 -j ACCEPT
/sbin/ip6tables -A FORWARD -m state --state NEW -i eth0 -o eth1 -j ACCEPT
/sbin/ip6tables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
/sbin/ip6tables -P INPUT DROP
/sbin/ip6tables -P FORWARD DROP
/sbin/ip6tables -P OUTPUT DROP
```

Original issue reported on code.google.com by `fltemp...@gmail.com` on 31 May 2013 at 6:05