Fix log-uninitialized-stack bug in rend_service_intro_established.

Fixes bug 23490; bugfix on 0.2.7.2-alpha.

TROVE-2017-008
CVE-2017-0380
rend_service_free_all(void)
{
  if (!rend_service_list)
    return;

  SMARTLIST_FOREACH(rend_service_list, rend_service_t*, ptr,
                    rend_service_free(ptr));
  smartlist_free(rend_service_list);
  rend_service_list = NULL;
}

rend_service_free_all(void)
{
  if (!rend_service_list)
    return;

  SMARTLIST_FOREACH(rend_service_list, rend_service_t*, ptr,
                    rend_service_free(ptr));
  smartlist_free(rend_service_list);
  rend_service_list = NULL;
}
