tangentlabs/django-oscar — pull request #745 by izidormatusov (2013-07-16 09:44:59+00:00)
Title: Shipping offers are included even with zero discount

There needs to be a check to ensure that shipping discounts are only included if they actually give a discount.

Evidence:
![image](https://f.cloud.github.com/assets/80975/762510/5fd4bce0-e7e9-11e2-9919-d198c15fc72a.png)