Comment 7 for bug 1708965

Reviewed: https://review.openstack.org/519201
Committed: https://git.openstack.org/cgit/openstack/tripleo-common/commit/?id=7e0564106e7b01f6516c22b95082b04bc0c8fc63
Submitter: Zuul
Branch: master

commit 7e0564106e7b01f6516c22b95082b04bc0c8fc63
Author: Steve Baker <email address hidden>
Date: Mon Nov 13 10:06:58 2017 +1300

    Implement post-upload cleanup of docker images

    The docker uploader will leave a copy of all uploaded images in the
    local docker storage. This change will track those images and delete
    them from the local docker after all uploads are complete.

    If a local image is in use (for example, an already deployed
    containerised undercloud) then the delete will fail. In this case,
    only a warning is logged.

    Change-Id: Ic0424638b9ddbf77e10cfe936d0b96ff2da1a59e
    Closes-Bug: #1708965
    Closes-Bug: #1694709