Comment 4 for bug 1823579

Reviewed: https://review.openstack.org/651005
Committed: https://git.openstack.org/cgit/openstack/tripleo-common/commit/?id=a47e0129e6c4a64d5d16e16e9ba82091957eb2a2
Submitter: Zuul
Branch: master

commit a47e0129e6c4a64d5d16e16e9ba82091957eb2a2
Author: Steve Baker <email address hidden>
Date: Tue Apr 9 09:59:24 2019 +1200

    Use ContainerImageRegistryCredentials for registry auth

    This change passes the value of parameter
    ContainerImageRegistryCredentials to the authenticate method in
    container prepare. The value is a dict of dicts, so it is validated to
    be in the expected format before being used. This allows prepare tasks
    to pull or push from any registry which requires a username/password,
    which is required by downstream.

    Change-Id: I71b767d16a22c732cc18378cedf6c6599ccc5ae1
    Closes-Bug: #1823579