msvc error C4805 fix (#28156)
Summary:
Fixes MSVC error message
```
15>d:\pytorch-scripts\caffe2_builders\v141\pytorch\torch\csrc\jit\register_string_ops.cpp(173): error C4805: '|=': unsafe mix of type 'bool' and type 'int' in operation
15>d:\pytorch-scripts\caffe2_builders\v141\pytorch\torch\csrc\jit\register_string_ops.cpp(173): error C4805: '|': unsafe mix of type 'bool' and type 'int' in operation
15>d:\pytorch-scripts\caffe2_builders\v141\pytorch\torch\csrc\jit\register_string_ops.cpp(186): error C4805: '|=': unsafe mix of type 'bool' and type 'int' in operation
15>d:\pytorch-scripts\caffe2_builders\v141\pytorch\torch\csrc\jit\register_string_ops.cpp(186): error C4805: '|': unsafe mix of type 'bool' and type 'int' in operation
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28156
Differential Revision: D18115151
Pulled By: ezyang
fbshipit-source-id: ed67a2b1330dfd4c12858ae9ca181163c0c72e51
