legacy: dbdump refactoring fix
legacy: dbdump refactoring fix

* Adds missing functions from master to dbquery, which caused e.g.
  dbdump to not work. (closes #2088)

Signed-off-by: Lars Holm Nielsen <7eaffca9f7cd98839b5821d0d23e09ff764b82cd@cern.ch>

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