don't save if do not train

examples/run_squad2.py

@@ -1010,6 +1010,7 @@ def main():
     # Save a trained model
     model_to_save = model.module if hasattr(model, 'module') else model  # Only save the model it-self
     output_model_file = os.path.join(args.output_dir, "pytorch_model.bin")
+    if args.do_train:
         torch.save(model_to_save.state_dict(), output_model_file)
 
     # Load a trained model that you have fine-tuned