Return USER_OP_SUCCESS when force stopping a user

                        + relatedUserId);

                // We still need to stop the requested user if it's a force stop.

                if (force) {

                    Slog.i(TAG,

                            "Force stop user " + userId + ". Related users will not be stopped");

                    stopSingleUserLocked(userId, callback);

                    return USER_OP_SUCCESS;

                }

                return USER_OP_ERROR_RELATED_USERS_CANNOT_STOP;

            }