[custom domain] Saving admin options on repo redirects to <username>/<repo>/admin 404
== What I expected to happen: ==
When using bitbucket from a custom domain (in this case code.wallrazer.com), saving the admin options for a repo should redirect to <custom domain>/<repo>/admin/.
== What happened: ==
Saving the admin options for a repo incorrectly redirects to <custom domain>/<user>/<repo>/admin and 404s.