Make yolov3 exportable (#2630)
Summary:
Non-strict export is tightening its check around attr assignment. As a result, this model became unexportable. This PR fixes that by properly tracking the tensor attributes via buffers.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/2630
Reviewed By: BoyuanFeng
Differential Revision: D80185351
Pulled By: tugsbayasgalan
fbshipit-source-id: 23956253f35b9666105de883e2f96e348e7f37c0
