Write only a single file for updates - fixes reboot loop issues.

Files with spaces and special characters were causing reboot loops.

main/managementinterface.go

@@ -311,7 +311,7 @@ func handleUpdatePostRequest(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(404)
 		return
 	}
-	updateFile := fmt.Sprintf("/root/%s", handler.Filename)
+	updateFile := fmt.Sprintf("/root/update-stratux-v.sh")
 	f, err := os.OpenFile(updateFile, os.O_WRONLY|os.O_CREATE, 0666)
 	if err != nil {
 		log.Printf("Update failed from %s (%s).\n", r.RemoteAddr, err.Error())