FreeTDM: fixing OPC bug using local SPC

           - take the DPC of the link and set it as OPC in x-header
           - this is what the user want's to have

libs/freetdm/src/ftmod/ftmod_sangoma_ss7/ftmod_sangoma_ss7_handle.c

@@ -253,7 +253,7 @@ ftdm_status_t handle_con_ind(uint32_t suInstId, uint32_t spInstId, uint32_t circ
 			sngss7_add_var(sngss7_info, "ss7_cic", var);
 
 
-			sprintf(var, "%d", g_ftdm_sngss7_data.cfg.isupIntf[sngss7_info->circuit->infId].spc );
+			sprintf(var, "%d", g_ftdm_sngss7_data.cfg.isupIntf[sngss7_info->circuit->infId].dpc );
 			sngss7_add_var(sngss7_info, "ss7_opc", var);
 			
 			if (siConEvnt->callRef.callId.pres) {