Fix compute max on empty version list

            url_fd = urlopen(url_req, timeout=timeout)

            logging.debug("Version regex: %s" % regex)

            v = re.findall(regex, url_fd.read().decode("utf-8"))

            if v is None:

            if v is None or len(v) == 0:

                raise VersionNotFound("No regex match on upstream")

            # remove duplicity

            v = list(set(v))