Special case EOF errors to give a nicer log message.
Special case EOF errors to give a nicer log message.

When the server restarts a message explaining that the server closed the connection will be printed; when the client (the thing connecting to the proxy) closes the connection that will be printed out explicitly as well.

digiexchris/cloudsql-proxy,ankushagarwal/cloudsql-proxy,digiexchris/cloudsql-proxy,syoya/cloudsql-proxy,GoogleCloudPlatform/cloud-sql-proxy,syoya/cloudsql-proxy,pdecat/cloudsql-proxy,ankushagarwal/cloudsql-proxy,GoogleCloudPlatform/cloud-sql-proxy,pdecat/cloudsql-proxy