BZ #1169980: Disable firewalld before setting up iptables

https://bugzilla.redhat.com/show_bug.cgi?id=1169980

This will remove the firewalld package and ensure that iptables is
installed before setup.
Merge pull request #120 from bcrochet/bz/1169980

BZ #1169980: Disable firewalld before setting up iptables