Back out "[pytorch][PR] remove tools/setup_helpers/cudnn.py"
Summary:
Original commit changeset: abd9cd0244ca
(Note: this ignores all push blocking failures!)
Test Plan: none
Reviewed By: nairbv
Differential Revision: D17259003
fbshipit-source-id: d7e067eeb36192766c639bfcbc66f540ce8eb77e
