Update ruby.rb

Hey guy! 

so using this recipe with     `chef.run_list = [ "recipe[omnibus::lite]"  ]`

would fail with no real good reason in chef.        however copying the contents of ::ruby-lite into ::ruby and then running with `chef.run_list = [ "recipe[omnibus::default]"  ]` works just fine.      

This PR does that ..   not that I expect you to merge it ...  just figured it would be as good a place as any to show it didn't work as produced (  although that could be a user error on my end ).

Probably a better way to resolve it would be a chef attribute that can be set RubyLite => true|false  and have the ruby recipe use that to install ruby from source,  or use the local chef copy of it.