Fix inconsistency with initialize_config()

stechuhr_server/retention.py

@@ -67,7 +67,7 @@ def data_retention():
     logger.info('Starting data_retention() in {}'.format(APPLICATION_NAME))
 
     # Initialize the configuration (create a default one if needed)
-    config = initialize_config(APPLICATION_NAME, DEFAULT_CONFIG, logger)
+    config = initialize_config(logger)
     logger.info('Will delete entries older than {} days (as set in config)'.format(config["retention"]["duration"]))
 
     # Initialize the db, create a connection