Use create_if_necessary instead of a simpler creation

Using current_order with create_if_necessary creates order that are
much more complete adding info about the ip, creator and other meta
data that is better to have rather than not. Not to mention that it's
also more readable.

frontend/app/controllers/spree/orders_controller.rb

@@ -39,7 +39,7 @@ def update
 
     # Shows the current incomplete order from the session
     def edit
-      @order = current_order || Spree::Order.incomplete.find_or_initialize_by(guest_token: cookies.signed[:guest_token])
+      @order = current_order(create_order_if_necessary: true)
       authorize! :read, @order, cookies.signed[:guest_token]
       associate_user
       if params[:id] && @order.number != params[:id]