Follow up for CI jobs refactoring

This changes addresses few comments left in the change that
refactored some of our CI jobs [1], regarding a more suggestive
anchor name and a comment to give more context for code reviewers
in the future.

[1] https: //review.opendev.org/c/openstack/manila-tempest-plugin/+/847366

Change-Id: I4abf0d60e6662c6f409bfa6506ab51ea717dc8cf
2 files changed