After introducing a new set of layer-specific `sources.list` files in
[1], we can now update the `DIST_REPOS` of this image to additionally
use the `openstack` layer binary repository when searching for
dependencies of packages listed in `DIST_PACKAGES`.
This ensures that OpenStack Antelope packages will be built *without* OpenStack Victoria dependencies.
[1] https://review.opendev.org/c/starlingx/root/+/896277
Test Plan:
PASS - Build `stx-debian` base image
PASS - Build `stx-openstackclients` container image and confirm that
OpenStack Antelope dependencies were used in the build of
`python3-cinderclient` and `python3-openstackclient`
Depends-On: https://review.opendev.org/c/starlingx/root/+/896277
Closes-Bug: 2037339
Change-Id: If94d5281c5c2633b59a6aaf39f0881fb5cec61bb
Signed-off-by: Luan Nunes Utimura <LuanNunes.Utimura@windriver.com>