Change order updater to refresh shipment rates and amounts on change

* This change will refresh the shipment rates and amounts when a
* completed order state changes.

  One specific example would be if the order line item quantity is
  changed in the admin menus we want the order shipment and shipping
  total to update.
Update Spree::OrderContents#reload_totals to update the order state

* The update logic is nearly identical, but is missing some methods and
  using it here unifies the behaviour.
Merge pull request #2 from bloomcrush/refresh-shipment-rates-on-order-change-mrh

Refresh shipment rates on order change mrh