[dataimport] prepare_insert_entity should not crash with SQLGenObjectStore
grafted from 1079d68130e1e780791ceb2050e8a8b7a910f48d (3.22)
related to #9177565.
missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules.tmpl)