Fix failing annotator login test on OSX

The `SERVER_NAME` environment variable on OSX defaults to 127.0.0.1 where on other systems it's localhost. When a user is created the provider defaults to the request.server_name value, this caused the assertion to fail.

Ideally we'd be able to set the SERVER_NAME in the config for all platforms, but I was unable to find the correct config value for this. So in the mean time I'm just accepting both options as valid.

Does anyone have any idea how to modify the default server environment? I tried:

```ini
;development.ini
[server:main]
use: egg:gunicorn
host: localhost
port: 5000
worker_class: gevent
env: SERVER_NAME=localhost
```