Make vagabond kitchen  play nice with berkshelf

The issue before this patch was that the cookbook loader would load with a Cheffile using the metadata for the cook. All good and dandy till you have a Berksfile that points to git branches and the such.  

This breaks it up so that if there is a berksfile it will use it to load the cooks for the solo run. If no berksfile then the old behavior is preserved.