fixed problems reported by certification testing : vendor identifier acces rights (now read only), and bvlc_maintenance timer was increasing too fast.
<?xml version='1.0' encoding='utf-8'?>
<BACnetServerNode xmlns:xsd="http://www.w3.org/2001/XMLSchema" UDP_Port_Number="47808" BACnet_Device_ID="3" BACnet_Communication_Control_Password=" " BACnet_Device_Location="Beremiz lab" Network_Interface="virbr0"/>