Fix 2024.1 job definitions

Set override-checkout: unmaintained/2024.1 as is done
in definitions for other branch jobs.

Changed override-checkout of neutron-tempest-plugin
to tag 2.12.0 as 2024.1-last is actually 3.0.0,
which contains a neutron-lib requirements bump that
breaks the jobs.

Removed upper-constraint changes from this change,
reverting most of it:

  https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/967479

Change-Id: I06d2374734cc888e294eb2d89cda452e60d92574
Signed-off-by: Brian Haley <haleyb.dev@gmail.com>
1 file changed