modules/ims_charging: fixes always true comparison of unsigned int

modules/ims_charging/ro_timer.c

@@ -409,7 +409,7 @@ void ro_session_ontimeout(struct ro_tl *tl) {
             counter_add(ims_charging_cnts_h.billed_secs, used_secs);
 
             if (ro_session->callid.s != NULL
-                    && ro_session->dlg_h_entry >= 0
+                    && ro_session->dlg_h_entry > 0
                     && ro_session->dlg_h_id > 0
                     && ro_session->ro_session_id.s != NULL) {
                 LM_DBG("Found a session to re-apply for timing [%.*s] and user is [%.*s]\n",