[caffe2][a10] Remove unreferenced local variable e (#48601)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48601
Fix this spurious warning:
```
caffe2\aten\src\aten\core\ivalue_inl.h(412): warning C4101: 'e': unreferenced local variable
```
Test Plan: Local build & continuous integration
Reviewed By: gmagogsfm
Differential Revision: D25194281
fbshipit-source-id: 3ba469d1cbff6f16394b95c4c33d95efcaea5e3e
