Use login URL from settings in menu.

biscuit/core/menus.py

+from django.conf import settings
 from django.utils.translation import ugettext_lazy as _
 
 MENUS = {
@@ -14,7 +15,7 @@ MENUS = {
                 },
                 {
                     'name': _('Login'),
-                    'url': 'two_factor:login',
+                    'url': settings.LOGIN_URL,
                     'validators': ['menu_generator.validators.is_anonymous']
                 },
                 {