Comment 6 for bug 1708967

Reviewed: https://review.openstack.org/500438
Committed: https://git.openstack.org/cgit/openstack/tripleo-common/commit/?id=45acbce815d42468288276c694f6597e04b7603d
Submitter: Jenkins
Branch: stable/pike

commit 45acbce815d42468288276c694f6597e04b7603d
Author: Steve Baker <email address hidden>
Date: Mon Aug 21 16:58:09 2017 +1200

    Upload remove default for pull_source

    Currently the pull_source defaults to "docker.io". This is unnecessary
    as docker.io is the default registry anyway when no registry is
    specified in the namespace.

    Also having this default prevents fully qualified image paths being
    specified in the imagename. This is desirable now that we use full
    paths in the heat parameters.

    This also allows the prepare command to deprecate the --pull-source
    argument and document having full image paths in the --namespace
    argument.

    Change-Id: I1769c7cf1c058328a8490228bdc4719e8d216ccb
    Partial-Bug: #1708967
    (cherry picked from commit c58ac826df6628629eeddf9e9a5b2f2be5578191)