Make placeholder images https enabled.

[tochev]

Loading http resources on https connection causes warnings and browsers,
depending on their configuration, will refuse to load them.

The change from placehold.it to dummyimage.com was necessitated by the
lack of https support on the later.

[amercader]

@tochev Thanks for this. Rather than relying on a third party service, I think a much better solution than the current one is serving the placeholder image from CKAN itself, to avoid other problems with network connectivity.
Can you add these two images (and any other that is using placehold.it) to the images folder and change the templates to something like src={{ h.url_for_static('/base/images/placeholder.png') }}

https://github.com/ckan/ckan/tree/master/ckan/public/base/images

For extra bonus, if you add locally the "open data" badge on the footer as well that would be awesome :)

https://github.com/ckan/ckan/blob/master/ckan/templates/footer.html#L17

Thanks

[tochev]

I will do it this weekend.

[amercader]

@tochev do you want to have a go a this? otherwise I'll do it

[amercader]

Closed in favour of #2119, thanks @tochev for the original patch

[tochev]

@amercader , sorry, I got caught in other things.