LOCK should be UNLOCK

LOCK should be UNLOCK

*** CID 306731:  Program hangs  (LOCK)
/lib/dns/resolver.c: 8943 in spillattimer_countdown()
8937     		result = isc_timer_reset(res->spillattimer,
8938     					 isc_timertype_inactive, NULL,
8939     					 NULL, true);
8940     		RUNTIME_CHECK(result == ISC_R_SUCCESS);
8941     	}
8942     	count = res->spillat;
   CID 306731:  Program hangs  (LOCK)
   "pthread_mutex_lock" locks "res->spill_lock" while it is locked.
8943     	LOCK(&res->spill_lock);
8944     	UNLOCK(&res->lock);
8945     	if (logit)
8946     		isc_log_write(dns_lctx, DNS_LOGCATEGORY_RESOLVER,
8947     			      DNS_LOGMODULE_RESOLVER, ISC_LOG_NOTICE,
8948     			      "clients-per-query decreased to %u", count);