nua_session.c: fix crash if session was terminated while INVITE was in progress

darcs-hash:20080516142826-db55f-8df439d30dd8ffe2fe7c01dc487d7b2276d49aaf.gz

libsofia-sip-ua/nua/nua_session.c

@@ -3714,7 +3714,7 @@ static int nua_bye_client_report(nua_client_request_t *cr,
       return 1; /* Application problem */
     }
 
-    cr->cr_usage = NULL;
+    nua_client_bind(cr, NULL);
 
     signal_call_state_change(nh, ss, status, "to BYE", 
 			     nua_callstate_terminated);