We've known for quite some time that maintaining a list of packages for image builds [2] is not ideal.  We need to push this review along [1].  This relies on DIB for the package list vs.. us specifying the list in the variables.

We're going to make this a priority now.

Please review [1]

Thanks!

[1] https://review.gerrithub.io/#/c/280666

[2] https://github.com/redhat-openstack/ansible-role-tripleo-image-build/