Revert D29922299: [DDP] log bucket sizes
Test Plan: revert-hammer
Differential Revision:
D29922299 (https://github.com/pytorch/pytorch/commit/5429f68f00a3525aca7dc2e1aeb913a8e0e2f406)
Original commit changeset: 538b331c96e7
fbshipit-source-id: 3595fe04e8dea38bc9d05e8c70f2dcd2ad496ced
