tests: cascading deletes on PostgreSQL
tests: cascading deletes on PostgreSQL

Signed-off-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

inveniosoftware/invenio-records,tiborsimko/invenio-records,tiborsimko/invenio-records,inveniosoftware/invenio-records