MSC_ConnectionHandler: fix f_rsl_reply() for RSL_MT_ENCR_CMD

For some weird reason the link_id is *not* the second IE in
RSL_MT_ENCR_CMD, while it is in all other RSL RLL or DCHAN messages.

Change-Id: Iea93aa8dba74d25c74a257d011ba43308ee375e4
diff --git a/bsc/MSC_ConnectionHandler.ttcn b/bsc/MSC_ConnectionHandler.ttcn
index 028f1b4..51ac650 100644
--- a/bsc/MSC_ConnectionHandler.ttcn
+++ b/bsc/MSC_ConnectionHandler.ttcn
@@ -95,7 +95,7 @@
 
 function f_rsl_reply(template PDU_ML3_MS_NW l3, RSL_Message orig) runs on MSC_ConnHdlr {
 	var RslChannelNr chan_nr := orig.ies[0].body.chan_nr;
-	var RslLinkId link_id := orig.ies[1].body.link_id;
+	var RslLinkId link_id;
 	if (orig.msg_type == RSL_MT_ENCR_CMD) {
 		link_id := orig.ies[2].body.link_id;
 	} else {