config: fix message generation when device is offline

lib/solaar/configuration.py

@@ -188,7 +188,7 @@ def persister(device):
     if not entry:
         if not device.online and not device.serial:  # don't create entry for offline devices without serial number
             if _log.isEnabledFor(_INFO):
-                _log.info('not creating persister for device %s', device.get('name'))
+                _log.info('not setting up persister for offline device %s with missing serial number', device.name)
             return
         entry = _DeviceEntry()
         _config.append(entry)