Fix directory called on _walk_directory

invokeai/backend/model_manager/search.py

@@ -141,7 +141,7 @@ def search(self, directory: Union[Path, str]) -> Set[Path]:
             self._directory = self.config.models_path / self._directory
         self.stats = SearchStats()  # zero out
         self.search_started()  # This will initialize _models_found to empty
-        self._walk_directory(directory)
+        self._walk_directory(self._directory)
         self.search_completed()
         return self.models_found