Replace rounding_mode="true" with rounding_mode=None (#51988)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51988
* **#51988 Replace rounding_mode="true" with rounding_mode=None**
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D27561817
Pulled By: mruberry
fbshipit-source-id: 60d1d9c389570f60d599fc1876518717367fb368
