workflows: Holding Pen details fix
workflows: Holding Pen details fix

* Fixes a problem where the detailed page for Holding Pen
  object caused an exception when information on next/previous
  objects from the table were missing.

Signed-off-by: Jan Aage Lavik <8d55e006a1b29770f275a5c59a7341f17f8e69d5@cern.ch>

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