SD probe: fix return value symbolic constant

modules/services_discovery/udev.c

@@ -68,7 +68,7 @@ static int vlc_sd_probe_Open (vlc_object_t *obj)
 
     struct udev *udev = udev_new ();
     if (udev == NULL)
-        return VLC_EGENERIC;
+        return VLC_PROBE_CONTINUE;
 
     struct udev_monitor *mon = udev_monitor_new_from_netlink (udev, "udev");
     if (mon != NULL)

modules/services_discovery/xcb_apps.c

@@ -77,7 +77,7 @@ static int vlc_sd_probe_Open (vlc_object_t *obj)
     xcb_connection_t *conn = xcb_connect (display, NULL);
     free (display);
     if (xcb_connection_has_error (conn))
-        return VLC_EGENERIC;
+        return VLC_PROBE_CONTINUE;
     xcb_disconnect (conn);
     return vlc_sd_probe_Add (probe, "xcb_apps", N_("Screen capture"));
 }