Detect ControlVault devices without NFC reader and show error

 cvcomm.py

@@ -59,11 +59,20 @@
        self.logger.debug('Enumerating interfaces...')
        configuration = self.device.get_active_configuration()
        bcm_interface = None
        has_contacted = False
        has_contactless = False
        for interface in configuration:
            if interface.bInterfaceClass == 0xff:
                if bcm_interface is not None:
                    raise Exception('More than one vendor-specific interface found!')
                bcm_interface = interface
            if interface.bInterfaceClass == 0xb:
                if interface.iInterface == 0x5:
                    has_contacted = True
                if interface.iInterface == 0x6:
                    has_contactless = True
        if not has_contactless:
            raise Exception('No contactless reader on this device!')
        if bcm_interface is None:
            raise Exception('Cannot find vendor-specific interface')
        self.logger.debug('Interface found: {}'.format(bcm_interface._str()))