When downloading a file with a space, the Content-Disposition header is malformed

For example content/geocaching/shared/Le robot gardien et la machinerie oubliée.docx is served with the following header:

`Content-Disposition: attachment; filename=Le robot gardien et la machinerie oubliée.docx`

It should be served with:

`Content-Disposition: attachment; filename="Le robot gardien et la machinerie oubliée.docx"`