remove custom calculator no longer needed with the new Spree shipping calculator.

app/models/spree/order_decorator.rb

@@ -17,15 +17,4 @@ Spree::Order.class_eval do
     end
   end
 
-  # UPGRADE_CHECK this works as of spree 1.2.0. check function for changes on upgrade
-  def available_shipping_methods(display_on = nil)
-    return [] unless ship_address
-    all_methods = Spree::ShippingMethod.all_available(self, display_on)
-
-    if self.digital?
-      all_methods.detect { |m| m.calculator.class == Spree::Calculator::DigitalDelivery }.try { |d| [d] } || all_methods
-    else
-      all_methods
-    end
-  end
 end