Bug 24267: (QA follow-up) Remove two calls, add transaction

Bug 24267: (QA follow-up) Remove two calls, add transaction

Call to GetAuthorizedHeading is already done just before calling ImportBreedingAuth.
Call to GuessAuthTypeCode is not used.
Adding transaction to test (check your database, kidclamp ;)

Test plan:
Add new authority via Z3950 in the interface.
Run t/db_dependent/Breeding.t

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>