properly receive BSSMAP Clear Complete and Iu Release Complete

When sending a BSSMAP Clear or Iu Release, do not immediately discard the conn,
but wait until a BSSMAP Clear Complete / Iu Release Complete has been received.

Hence we will no longer show in the log that an incoming Release/Clear Complete
belongs to an unknown subscriber, but will still be around to properly log the
release.

Related: OS#3122
Change-Id: Ie4c6aaba3866d6e5b98004e8870a215e8cf8ffc1
diff --git a/src/libmsc/iucs_ranap.c b/src/libmsc/iucs_ranap.c
index 57cd50e..ec0b569 100644
--- a/src/libmsc/iucs_ranap.c
+++ b/src/libmsc/iucs_ranap.c
@@ -117,7 +117,7 @@
 	case RANAP_IU_EVENT_LINK_INVALIDATED:
 		LOGP(DIUCS, LOGL_INFO, "IuCS release for %s\n",
 		     vlr_subscr_name(conn->vsub));
-		msc_subscr_conn_close(conn, 0);
+		msc_subscr_conn_rx_iu_release_complete(conn);
 		return 0;
 
 	case RANAP_IU_EVENT_SECURITY_MODE_COMPLETE: