write_stylus: fix error "cannot download icon.tar.gz from any mirror"

error message was

```
trying https://oyra.eu/write/icon.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (22) The requested URL returned error: 404 Not Found
error: cannot download icon.tar.gz from any mirror
```