login: Log redirection target on debug level

We have some magic when computing the URL, it is good if we can see in the debug
log this detail.

rhodecode/login/views.py

@@ -154,6 +154,7 b' class LoginView(object):'
                 self.session,
                 username=form_result['username'],
                 remember=form_result['remember'])
+            log.debug('Redirecting to "%s" after login.', came_from)
             raise HTTPFound(came_from, headers=headers)
         except formencode.Invalid as errors:
             defaults = errors.value