The call to http.Server.Shutdown in main.go that happens on os.Interrupt
closes listeners. Remove racey code and format network/network.go.
Running Listener.Accept in a loop is not necessary as the stdlib expects
SA_RESTART to be set for signal handlers.
This makes systemd not put unit into fail mode when stopping
INFO:
* make sure to use signals.RegisterCloser for everything that should be closed on interrupt
* for any net.Listeners created make sure to wrap them with network.WrapListener and register with signals.RegisterCloser
