BibUpload: verbose post_results_to_callback_url()
BibUpload: verbose post_results_to_callback_url()

* Improves verbosity of post_results_to_callback_url() to make
  debugging with external systems easier.

tiborsimko/invenio,inveniosoftware/invenio,tiborsimko/invenio,inveniosoftware/invenio