BibConvert: 980__a:PUBLISHED removed for arXiv

Signed-off-by: Georgios Papoutsakis <georgios.papoutsakis@cern.ch>
BibConvert: record type guessing removal

* Removes the guessing of record types such as Published,Thesis
  and ConferencePaper.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>