oaiharvester: refextract task fix

* Checks properly if the PDF is downloaded successfully inside the
  refextract task.

Reviewed-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Signed-off-by: Georgios Papoutsakis <georgios.papoutsakis@cern.ch>
template: fix for unicode url handling

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>