Remove unnecessary to_string in RPC logging code. (#38414)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38414
`std::to_string` call is unnecessary when using glog.
ghstack-source-id: 104030161
Test Plan: Ran the retry tests and checked logs to ensure correct message was printed upon message failure,
Differential Revision: D21266330
fbshipit-source-id: 53519287778d47d99b94ea34b7c551f910affda2
