Revert D29816592: [pytorch][PR] [fix] polygamma n>=1
Test Plan: revert-hammer
Differential Revision:
D29816592 (https://github.com/pytorch/pytorch/commit/b73d7597089c6d27f3b3894e11d9266bd427d1e6)
Original commit changeset: 2c020a6e4c32
fbshipit-source-id: 310c93ade300966366ef04f206a5908fb27745db
