throw error if not config file found

corrlib/tracker.py

@@ -9,6 +9,8 @@ def get_tracker(path: str) -> str:
     config = ConfigParser()
     if os.path.exists(config_path):
         config.read(config_path)
+    else:
+        raise FileNotFoundError(f"No config file found in {path}.")
     tracker = config.get('core', 'tracker', fallback='datalad')
     return tracker