Fix panic when https server is not running

control.go

@@ -1086,7 +1086,7 @@ func handleTLSConfigure(w http.ResponseWriter, r *http.Request) {
 	httpUpdateConfigReloadDNSReturnOK(w, r)
 	// this needs to be done in a goroutine because Shutdown() is a blocking call, and it will block
 	// until all requests are finished, and _we_ are inside a request right now, so it will block indefinitely
-	if restartHTTPS {
+	if restartHTTPS && httpsServer.server != nil {
 		go func() {
 			httpsServer.cond.Broadcast()
 			httpsServer.server.Shutdown(context.TODO())