Wrong tag in template/debian/release_info.wml

Hi -www team,

We were notified [1] of a broken link to the unofficial non-free images 
from the page :
https://www.debian.org/releases/jessie/debian-installer/

I think it comes from :
english/template/debian/release_info.wml
where non-free-cd-release is defined as cd-release :
> # non-free cd including firmware are not always in sync
> <define-tag 
> current-nonfree-cd-release-dirname><current-cd-release/></define-tag>
instead of being defined as 8.5.0+nonfree.

[1] https://lists.debian.org/debian-l10n-french/2016/06/msg00098.html

Thanks
Baptiste, not sure enough to commit a change in the templates !