Vendor the external cookbooks

Knife-Zero doesn't include Berkshelf support, so vendoring everything in
the repo is convenient again

cookbooks/git/libraries/provider_git_client.rb

@@ -0,0 +1,13 @@
+class Chef
+  class Provider
+    class GitClient < Chef::Provider::LWRPBase
+      use_inline_resources
+
+      def whyrun_supported?
+        true
+      end
+
+      include GitCookbook::Helpers
+    end
+  end
+end