[to #42322933] Fix bug for distributed gpt3

修复 Pipeline 更新后 DistributedGPT3Pipeline 出现的报错
        Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/10614071

modelscope/pipelines/base.py

@@ -366,6 +366,7 @@ class DistributedPipeline(Pipeline):
                 master_port=master_port,
                 **self.cfg.model,
                 **kwargs), ranks)
+        self.models = []
 
     def __del__(self):
         if hasattr(self, 'model_pool') and self.model_pool is not None: