previewer: pdfjs previewer hotfix

* Fixes the problem with pdfjs previewer scripts loading.

Signed-off-by: Adrian Pawel Baran <adrian.pawel.baran@cern.ch>
bibdocfile: pdfjs previewer hot fix

* Fixes issues with files being loaded over http instead of https.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>