sgsn: make the ranap interface optional

Allows to use the test cases without STP

Change-Id: I43df456c2d5aa3ba3ea9e34da3f0f96b55f7c9a1
diff --git a/sgsn/SGSN_Tests_Iu.ttcn b/sgsn/SGSN_Tests_Iu.ttcn
index ace295c..2f077d8 100644
--- a/sgsn/SGSN_Tests_Iu.ttcn
+++ b/sgsn/SGSN_Tests_Iu.ttcn
@@ -28,6 +28,7 @@
 	 * MS -> SGSN: Attach Complete
 	 */
 	var BSSGP_ConnHdlr vc_conn;
+	g_ranap_enable := true;
 	f_init();
 	f_sleep(1.0);
 	vc_conn := f_start_handler(refers(f_TC_iu_attach), testcasename(), g_gb, 1001);