pass whole config, not just cookbook_path

This was causing an issue (#140) because we were
passing an Array instead of a Hash.
Compare the two following links:

https://github.com/opscode/chef/blob/11.14.6/lib/chef/cookbook_uploader.rb#L39
https://github.com/opscode/chef/blob/12.0.0.alpha.1/lib/chef/cookbook_uploader.rb#L38