[TensorPipe Agent] Message on Agent Shutdown (#38819)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38819
Logs a message when the agent is shutting down like the other RPC
Agents.
ghstack-source-id: 104673386
Test Plan: Sandcastle
Differential Revision: D21671061
fbshipit-source-id: a44f0e4976e3acc898645a2baf6f41f45a697166
