gap: Fix not handling accept properly

On accept the profile shall check about existing attribute, etc and once
done call btd_service_connecting_complete updating the service state
properly.
diff --git a/profiles/gap/gas.c b/profiles/gap/gas.c
index 35b996c..b10b6ac 100644
--- a/profiles/gap/gas.c
+++ b/profiles/gap/gas.c
@@ -300,6 +300,13 @@
 	bt_uuid16_create(&gap_uuid, GAP_UUID16);
 	gatt_db_foreach_service(db, &gap_uuid, foreach_gap_service, gas);
 
+	if (!gas->attr) {
+		error("GAP attribute not found");
+		return -1;
+	}
+
+	btd_service_connecting_complete(service, 0);
+
 	return 0;
 }