Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/firewall/attributes/iptables.rb

@@ -1,17 +0,0 @@
-default['firewall']['iptables']['defaults'][:policy] = {
-  input: 'DROP',
-  forward: 'DROP',
-  output: 'ACCEPT',
-}
-default['firewall']['iptables']['defaults'][:ruleset] = {
-  '*filter' => 1,
-  ":INPUT #{node['firewall']['iptables']['defaults'][:policy][:input]}" => 2,
-  ":FORWARD #{node['firewall']['iptables']['defaults'][:policy][:forward]}" => 3,
-  ":OUTPUT #{node['firewall']['iptables']['defaults'][:policy][:output]}" => 4,
-  'COMMIT_FILTER' => 100,
-}
-
-default['firewall']['ubuntu_iptables'] = false
-default['firewall']['redhat7_iptables'] = false
-default['firewall']['allow_established'] = true
-default['firewall']['ipv6_enabled'] = true