Bug 21749: Fix import of CSV biblio framework

Bug 21749: Fix import of CSV biblio framework

Bug 9701 added 2 new columns to the table marc_tag_structure which broke
the import of biblio frameworks if the CSV file was generated with a
previous version.

Test plan:
- Export a biblio framework from 17.11
- Import it into 18.05+

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
https://bugs.koha-community.org/show_bug.cgi?id=21740

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>