BZ #1103315 - Openstack firewall rules are not enabled after reboot.

https://bugzilla.redhat.com/show_bug.cgi?id=1103315

The firewall module we depend on doesnt yet account for firewalld, which is
enabled by default in RHEL 7.
Merge pull request #244 from jguiditta/icehouse_firewalld

BZ #1103315 - Openstack firewall rules are not enabled after reboot.