vlr_gsup_rx: fix uninitialized rc

Change-Id: Id7776a473b8356d1d136d78736698f20accc7a36
diff --git a/src/libvlr/vlr.c b/src/libvlr/vlr.c
index 1a753dc..f644df8 100644
--- a/src/libvlr/vlr.c
+++ b/src/libvlr/vlr.c
@@ -1069,7 +1069,7 @@
 {
 	struct vlr_instance *vlr = data;
 	struct vlr_subscr *vsub;
-	int rc;
+	int rc = 0;
 
 	vsub = vlr_subscr_find_by_imsi(vlr, gsup->imsi, __func__);
 	if (!vsub) {