[Dextrose] F18's firewalld in 13.1.0

[Jerry Vonau]

Hi all, 

With F18 moving to firewalld as the default firewalling method this has
rendered powerd's netactivity iptables chain to NOT be loaded at all.

How to reproduce:

sudo iptables -S
note that netactivity chain is not present.

sudo rpm -e firewalld 
reboot

sudo iptables -S 
note that netactivity chain is present.

Think the easy fix for right now is to exclude firewalld from the build
image in OOB.

Jerry