[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
diff --git a/torch/csrc/distributed/rpc/tensorpipe_agent.cpp b/torch/csrc/distributed/rpc/tensorpipe_agent.cpp
index f0a4c50..70074a4 100644
--- a/torch/csrc/distributed/rpc/tensorpipe_agent.cpp
+++ b/torch/csrc/distributed/rpc/tensorpipe_agent.cpp
@@ -493,6 +493,8 @@
 }
 
 void TensorPipeAgent::shutdownImpl() {
+  LOG(INFO) << "Shutting down TensorPipeAgent on node "
+            << RpcAgent::getWorkerInfo().name_;
   threadPool_.waitWorkComplete();
 
   // Join the Timeout Thread