fix torch bug

x2paddle/convert.py

@@ -110,6 +110,17 @@ def onnx2paddle(model_path, save_dir):
     except:
         print("onnx is not installed, use \"pip install onnx==1.5.0\".")
         return
+    try:
+        import torch
+        version = torch.__version__
+        if '1.1.0' not in version:
+            print("your model have dynamic graph, torch==1.1.0 is required")
+            return
+        except:
+            print(
+                "your model have dynamic graph, we use caff2 to inference graph, please use \"pip install torch==1.1.0\"."
+            )
+            return
     print("Now translating model from onnx to paddle.")
 
     from x2paddle.decoder.onnx_decoder import ONNXDecoder