Fixing torch2hpvm import issue in snippet

hpvm/projects/torch2hpvm/README.md

@@ -47,6 +47,7 @@ See TODOs (1).
 Create a DNN `module` and load the checkpoint:
 
 ```python
+import torch
 from torch.nn import Module
 import dnn  # Defined at `hpvm/test/dnn_benchmarks/pytorch`
 
@@ -106,4 +107,4 @@ This choice of operators is largely constrained by backend (tensor_runtime) supp
    - Needs pybind11, hardcoding of Python environment, and some fiddling with import mechanism.
 1. Expand the list of operators supported in the frontend.
    - Most ideally, create a high-level description of operators that can tie
-     HPVM-C intrinsics and the frontend list of operators together.
\ No newline at end of file
+     HPVM-C intrinsics and the frontend list of operators together.