Bug 23428: (bug 23151 follow-up) Fix self registration with a verification email

Bug 23428: (bug 23151 follow-up) Fix self registration with a verification email

DBIx::Class::Row::store_column(): No such column 'changed_fields' on
Koha::Schema::Result::Borrower at /home/vagrant/kohaclone/Koha/Object.pm
line 75

Test plan:
- Turn PatronSelfRegistrationVerifyByEmail on
- Register a new account
- Click on the link (see the message_queue table)
=> Without this patch you get the error
=> With this patch you will see the login form

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>