MSC_Tests: Allow test cases to specify RAN index

This allows to start ConnHdlr on specific RAN connections, i.e.
on different emulated BSCs (and soon RNCs).

Change-Id: I3d7ec567a7b69d8c6f79d26971bf1c94e077d5f5
diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index db0e683..4534a9b 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -74,7 +74,8 @@
 	boolean ipa_ctrl_enable,
 	boolean mm_info,
 	boolean sgsap_enable,
-	boolean gsup_enable
+	boolean gsup_enable,
+	integer ran_idx
 };
 
 /* get a one-octet bitmaks of supported algorithms based on Classmark information */