MaintenanceScript: Remove unused logic for required options
dbUpdate: Fix logic error in 9f4f6b1

Database::query only returns false if the query failed.
If it didn't fail but yielded 0 results it still returns
a valid MySqlResource object (which are alway truthy,
even if there is nothing to fetch).

Using Database::getOne instead, since mysql_fetch_* will
return false if there resource is empty.