[DS-2195] Ensure that a found Group's TableRow is typed.

DatabaseManager.querySingle returns an untyped TableRow.  We can't use
querySingleTable because the row contains columns not found in the
required type.  Just force the row to have a type anyway, since it
does contain all of the columns required for that type.  Otherwise the
Group is not update()able.
Merge pull request #718 from mwoodiupui/DS-2195

[DS-2195] importing AIPs with DSpace:master throws an NPE