(GH-134) Autorequire iptables related packages

autorequires from firewall and firewallchain resources to iptables and
iptables-persistent packages, when the appropriate provider is selected and
the packages are managed in the catalog. This will prevent failed rule
creation and persistence on fresh nodes where the packages may not be
pre-installed.
Merge pull request #136 from dcarley/134-autorequire_packages

(GH-134) Autorequire iptables related packages