Revert D27709912: TCPStore add watchKey method and new listener thread
Test Plan: revert-hammer
Differential Revision:
D27709912 (https://github.com/pytorch/pytorch/commit/f8f756efb25d942053f293909c14e6c0dd81123b)
Original commit changeset: 619aa3b2a8eb
fbshipit-source-id: 3ef96ccaa76c702d7e5427dfc263531fb1c274ab
