[util] fixed communication API depth with PyTorch 1.9 (#721)

colossalai/communication/collective.py

@@ -211,7 +211,7 @@ def reduce(tensor: Tensor,
 def scatter_object_list(scatter_object_output_list, scatter_object_input_list, src=0, group=None):
     r"""Modified from `torch.distributed.scatter_object_list <https://pytorch.org/docs/stable/_modules/torch/distributed/distributed_c10d.html#scatter_object_list>` to fix issues
     """
-    if dist._rank_not_in_group(group):
+    if dist.distributed_c10d._rank_not_in_group(group):
         return
 
     if (not isinstance(scatter_object_output_list, list) or len(scatter_object_output_list) < 1):