method should always return the same type

frontend-js/src/main/js/ServerConnector.js

@@ -1242,7 +1242,7 @@ ServerConnector.updateUser = function (user) {
     return self.getConfiguration();
   }).then(function (configuration) {
     if (!canModifyPrivileges) {
-      return Promise.resolve();
+      return Promise.resolve(user);
     }
     return self.updateUserPrivileges({user: user, privileges: user.privilegesToExport(configuration)});
   });