Bug 19910: Use the delimiter syspref to name download link

Bug 19910: Use the delimiter syspref to name download link

To test:
1 - Set delimiter syspref to anything but comma
2 - Download report results as comma separated text
3 - They actually follow the syspref
4 - Apply patch
5 - Download link should now match pref selection
6 - Change pref, note link changes
7 - Verify things still work as expected

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Victor Grousset <victor.grousset@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>