[to #42322933] Fix bug for DistributedPipeline

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/10913762

modelscope/pipelines/base.py

@@ -384,12 +384,17 @@ class DistributedPipeline(Pipeline):
                  preprocessor: Union[Preprocessor, List[Preprocessor]] = None,
                  auto_collate=True,
                  **kwargs):
-        super().__init__(model=model, preprocessor=preprocessor, kwargs=kwargs)
+        # DistributedPipeline uses classmethod to initialize model
+        # without calling super().__init__ method
+        self.preprocessor = preprocessor
         self._model_prepare = False
         self._model_prepare_lock = Lock()
         self._auto_collate = auto_collate
 
-        self.model_dir = self.model.model_dir
+        if os.path.exists(model):
+            self.model_dir = model
+        else:
+            self.model_dir = snapshot_download(model)
         self.cfg = read_config(self.model_dir)
         self.world_size = self.cfg.model.world_size
         self.model_pool = None