Provide a bit more information in the log why it failed

jail2ban/__init__.py

@@ -191,6 +191,8 @@ def create_app():
         Show a json parsable error if the value is illegal
         '''
         app.logger.fatal(error)
+        app.logger.fatal('stdout: %s', error.stderr)
+        app.logger.fatal('stderr: %s', error.stderr)
         return jsonify({'error': str(error)}), 500
 
     @app.errorhandler(FileNotFoundError)