retry wont work if retry_timeout not set, is this intentional? #145

    def retry(self, payload_class, args):
        """This method provides a way to retry a job after a failure.
        If the jobclass defined by the payload containes a ``retry_every`` attribute then pyres
        will attempt to retry the job until successful or until timeout defined by ``retry_timeout`` on the payload class.
        """
        retry_every = getattr(payload_class, 'retry_every', None)
        retry_timeout = getattr(payload_class, 'retry_timeout', 0)

        if retry_every:
            now = ResQ._current_time()
            first_attempt = self._payload.get("first_attempt", now)
            retry_until = first_attempt + timedelta(seconds=retry_timeout)
            retry_at = now + timedelta(seconds=retry_every)
            if retry_at < retry_until:
                self.resq.enqueue_at(retry_at, payload_class, *args,
                        **{'first_attempt':first_attempt})
                return True
        return False