Revert D29132955: Pass RequestCallback to FaultyPG RPC agent
Test Plan: revert-hammer
Differential Revision:
D29132955 (https://github.com/pytorch/pytorch/commit/cbbb7e145e770213146bab1fc36c6abe1865d857)
Original commit changeset: bb7554b84bcb
fbshipit-source-id: 4dfa2fbe7b8f58c951991c79aa9e2aa819793013
