FreeTDM: reuse sip_h_X-FreeTDM-LOC = NULL to indicate disable LOC

libs/freetdm/mod_freetdm/mod_freetdm.c

@@ -1527,9 +1527,6 @@ static switch_call_cause_t channel_outgoing_channel(switch_core_session_t *sessi
 		ftdm_usrmsg_add_var(&usrmsg, "iam_fwd_ind_isdn_access_ind", var);
 	}
 
-	if ((var = channel_get_variable(session, var_event, "freetdm_iam_loc_pres"))) {
-		ftdm_usrmsg_add_var(&usrmsg, "iam_loc_pres", var);
-	}
 	if ((var = channel_get_variable(session, var_event, "freetdm_bearer_capability"))) {
 		caller_data.bearer_capability = (uint8_t)atoi(var);
 	}

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_support.c

@@ -248,15 +248,10 @@ ftdm_status_t copy_locPtyNum_to_sngss7(ftdm_channel_t *ftdmchan, SiCgPtyNum *loc
         sngss7_chan_data_t *sngss7_info = ftdmchan->call_data;
         ftdm_caller_data_t *caller_data = &ftdmchan->caller_data;
 
-
-        val = ftdm_usrmsg_get_var(ftdmchan->usrmsg, "iam_loc_pres");
-        if (!ftdm_strlen_zero(val)) {
-			if (!strcasecmp(val, "false")) {
-				pres_val = NOTPRSNT;
-			}
+		if (!strcasecmp(caller_data->loc.digits, "NULL")) {
+			pres_val = NOTPRSNT;
 		}
 
-
         locPtyNum->eh.pres = pres_val;
         locPtyNum->natAddrInd.pres = pres_val;
         locPtyNum->natAddrInd.val = g_ftdm_sngss7_data.cfg.isupCkt[sngss7_info->circuit->id].loc_nadi;