Stop tests after failures

Call mtc.stop after setverdict(fail), add reasons to most failures and
fail with verdict error for internal errors.

Change-Id: I9b618235939fa41160b9be6677b121963d3ec857
diff --git a/mgw/RTP_Endpoint.ttcn b/mgw/RTP_Endpoint.ttcn
index 3c939a2..c73aa58 100644
--- a/mgw/RTP_Endpoint.ttcn
+++ b/mgw/RTP_Endpoint.ttcn
@@ -111,7 +111,7 @@
 					sub.local_name, sub.local_port, sub.connection_id, { udp := {} });
 		if (not ispresent(res.connId)) {
 			setverdict(fail, "Could not connect RTP, check your configuration");
-			self.stop;
+			mtc.stop;
 		}
 		/* connect without previous bind: save conenction id allocated by IPL4asp */
 		if (sub.connection_id == -1) {
@@ -136,7 +136,7 @@
 		res := f_IPL4_listen(RTP, sub.local_name, sub.local_port, { udp := {} });
 		if (not ispresent(res.connId)) {
 			setverdict(fail, "Could not listen to RTP, check your configuration");
-			self.stop;
+			mtc.stop;
 		}
 		sub.connection_id := res.connId;
 	}