MSC_Tests.ttcn: use f_expect_gsup_msg() in f_tc_mt_ussd_for_unknown_subscr()

Change-Id: Id067cee3b7d06613d8387e0fa9d8a5c1dbcc49cf
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index b66323b..b8f9fd7 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -3474,7 +3474,6 @@
 runs on BSC_ConnHdlr {
 	var hexstring imsi := '000000000000000'H; /* Some unknown IMSI */
 	var OCT4 sid := '20000222'O;
-	timer T := 2.0;
 
 	f_init_handler(pars);
 	f_ran_register_imsi(imsi, 'FFFFFFFF'O);
@@ -3499,17 +3498,7 @@
 	GSUP.send(gsup_req);
 
 	/* Expect GSUP PROC_SS_ERROR message */
-	T.start;
-	alt {
-	[] GSUP.receive(gsup_rsp) {
-		setverdict(pass);
-		};
-	[] T.timeout {
-		setverdict(fail, "Timeout waiting for GSUP PROC_SS_ERROR message");
-		}
-	/* We don't expect anything else */
-	[] as_unexp_gsup_or_bssap_msg();
-	}
+	f_expect_gsup_msg(gsup_rsp);
 }
 testcase TC_mt_ussd_for_unknown_subscr() runs on MTC_CT {
 	var BSC_ConnHdlr vc_conn;