Diffusers 0.15.0 bug fix (#3345)

* diffusers 0.15.0 cross attention class check

* revert diffusers_attention.py

deepspeed/module_inject/replace_module.py

@@ -233,7 +233,10 @@ def generic_injection(module, fp16=False, enable_cuda_graph=True):
 
         try:
             import diffusers
+            if hasattr(diffusers.models.attention, 'CrossAttention'):
                 cross_attention = diffusers.models.attention.CrossAttention
+            else:
+                cross_attention = diffusers.models.attention_processor.Attention
             attention_block = diffusers.models.attention.BasicTransformerBlock
             new_policies = {
                 cross_attention: replace_attn,