Comment 4 for bug 1783518

Some notes at https://etherpad.openstack.org/p/tripleo-rpm-container-image-notes which I created in response to https://bugs.launchpad.net/tripleo/+bug/1788414, which may actually be a duplicate (or perhaps a more general case) of this bug.

I suspect we can write a small helper script which does the following (see etherpad for details):

1. Clone source & cherry-pick any changes
2. Create dockerfile for images we want to rebuild with the source dir above ADD'ed & steps to install from source
3. Build & push the new image via a temporary tag
4. Figure out which images in the various paunch configs are affected (e.g should be updated)
5. Update them and re-run paunch in order for the relevant steps