Implement IuCS (large refactoring and addition)

osmo-nitb becomes osmo-msc
add DIUCS debug log constant
add iucs.[hc]
add msc vty, remove nitb vty
add libiudummy, to avoid linking Iu deps in tests
Use new msc_tx_dtap() instead of gsm0808_submit_dtap()
libmgcp: add mgcpgw client API
bridge calls via mgcpgw

Enable MSC specific CTRL commands, bsc_base_ctrl_cmds_install() still needs to
be split up.

Change-Id: I5b5b6a9678b458affa86800afb1ec726e66eed88
diff --git a/src/libmsc/silent_call.c b/src/libmsc/silent_call.c
index 5fad4f4..7af7a80 100644
--- a/src/libmsc/silent_call.c
+++ b/src/libmsc/silent_call.c
@@ -133,7 +133,8 @@
 	/* FIXME the VTY command allows selecting a silent call channel type.
 	 * This doesn't apply to the situation after MSCSPLIT with an
 	 * A-interface. */
-	req = subscr_request_conn(vsub, type, paging_cb_silent, data);
+	req = subscr_request_conn(vsub, paging_cb_silent, data,
+				  "establish silent call");
 	return req != NULL;
 }