Overwrite PricesController#destroy to call #destroy

Price still responds to `#discard`, but  we really want to call
`#destroy`.

Author: mamhoff

backend/app/controllers/spree/admin/prices_controller.rb

@@ -23,6 +23,31 @@ def index
 
       def edit
       end
+
+      def destroy
+        invoke_callbacks(:destroy, :before)
+
+        if @object.destroy
+          invoke_callbacks(:destroy, :after)
+          flash[:success] = flash_message_for(@object, :successfully_removed)
+          respond_with(@object) do |format|
+            format.html { redirect_to location_after_destroy }
+            format.js   { render partial: "spree/admin/shared/destroy" }
+          end
+        else
+          invoke_callbacks(:destroy, :fails)
+          respond_with(@object) do |format|
+            message = @object.errors.full_messages.to_sentence
+            format.html do
+              flash[:error] = message
+              redirect_to location_after_destroy
+            end
+            format.js do
+              render status: :unprocessable_entity, plain: message
+            end
+          end
+        end
+      end
     end
   end
 end