Remove hard-wired '/' URLs from templates

From mailing list: Checkout page redirects to homepage:

![Screenshot](https://lh4.googleusercontent.com/-pwYVRWxVlJA/UjtZKx1FCoI/AAAAAAAAAVU/fmX7rxseTM0/s1600/Screen+Shot+2013-09-19+at+22.05.08+.png)