BibRank: missing selfcites for collaborations

• This fixes a bug that only occurs when not using bibauthorid and computing selfcites. We wouldn't collect enough authors for papers that were written by collaborations which means that we would never look at the collaboration name when computing self cites.

Signed-off-by: Alessio Deiana <alessio.deiana@cern.ch>
Tested-by: Tibor Simko <tibor.simko@cern.ch>