properly handle unknown transport protocols

daemon/call.c

@@ -1843,11 +1843,8 @@ int monologue_offer_answer(struct call_monologue *monologue, GQueue *streams,
 		 * offerer or WAS sent to the answerer. */
 
 		/* deduct protocol from stream parameters received */
-		if (!other_media->protocol) {
+		if (!other_media->protocol)
 			other_media->protocol = sp->protocol;
-			if (!other_media->protocol)
-				other_media->protocol = &transport_protocols[PROTO_RTP_AVP];
-		}
 		/* allow override of outgoing protocol even if we know it already */
 		if (flags && flags->transport_protocol)
 			media->protocol = flags->transport_protocol;

daemon/sdp.c

@@ -1174,7 +1174,7 @@ static int replace_transport_protocol(struct sdp_chopper *chop,
 	str *tp = &media->transport;
 
 	if (!cm->protocol)
-		return 0; /* XXX correct? or give warning? */
+		return 0;
 
 	if (copy_up_to(chop, tp))
 		return -1;