Make REMOTE_ADDR optional

Resolves #263

Author: samamorgan

easyaudit/signals/auth_signals.py

@@ -18,7 +18,7 @@ def user_logged_in(sender, request, user, **kwargs):
                 'login_type': LoginEvent.LOGIN,
                 'username': getattr(user, user.USERNAME_FIELD),
                 'user_id': getattr(user, 'id', None),
-                'remote_ip': request.META[REMOTE_ADDR_HEADER]
+                'remote_ip': request.META.get(REMOTE_ADDR_HEADER, "")
             })
     except Exception:
         if should_propagate_exceptions():