Header links in /login broken for logged in users.

[simpsonw]

Steps to reproduce

1. Go to /login and login as a user with admin rights.
2. After logging in a being redirected, mannually go to /login by typing it into your browser.
3. Click either "Admin" or "Change Password".

Expected Result

You will see either the "Admin" or "Change Password" page.

Actual Result

You get a 404. This appears to because the links end up being relative to /flex_auth.