Do not run probes if they don't support offline mode

When the probe doesn't implement offline mode function it means
the probe doesn't support offline mode, therefore it should
set the supported_offline_mode flag to PROBE_OFFLINE_NONE.
This omission caused that the probe was run and scanned the host.

Author: jan-cerny

src/OVAL/probes/probe/worker.c

@@ -969,6 +969,8 @@ SEXP_t *probe_worker(probe_t *probe, SEAP_msg_t *msg_in, int *ret)
 	probe_offline_mode_function_t offline_mode_function = probe_table_get_offline_mode_function(probe->subtype);
 	if (offline_mode_function != NULL) {
 		probe->supported_offline_mode = offline_mode_function();
+	} else {
+		probe->supported_offline_mode = PROBE_OFFLINE_NONE;
 	}
 
 	/*