msc: TC_lu_disconnect: add final delay to fix spurious failure

I hit a "Broken pipe" error, hoping that the bit of delay makes the teardown
more stable.

Change-Id: I765a75f91a748239f6cc82f4a61f02d59166f00b
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index 31a7401..d02a0ed 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -822,6 +822,7 @@
 	/* send clear request in the middle of the LU */
 	BSSAP.send(BSSAP_Conn_Prim:MSC_CONN_PRIM_DISC_REQ);
 	setverdict(pass);
+	f_sleep(1.0);
 }
 testcase TC_lu_disconnect() runs on MTC_CT {
 	var BSC_ConnHdlr vc_conn;