Comment 9 for bug 1682058

Reviewed: https://review.openstack.org/494688
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=8cb0e1f57033f697ec43819952ef07b43582b3d1
Submitter: Jenkins
Branch: stable/ocata

commit 8cb0e1f57033f697ec43819952ef07b43582b3d1
Author: Mark Goddard <email address hidden>
Date: Tue Jul 4 19:24:28 2017 +0100

    Don't poll heat if no stack exists

    Cluster objects are created asynchronously from their underlying
    heat stacks, meaning that the periodic update can sometimes end up
    trying to poll a cluster's heat stack before the stack has been created.

    This change checks whether the stack_id is None and skips polling heat
    if so. This has the side effect of resolving bug 1682058, since we don't
    try to use a trust and trustee that do not exist.

    Change-Id: I73f039659250f1d5b69b23141835c4602c8e019a
    Closes-Bug: #1682058
    (cherry picked from commit 88a6e3bab5f4af92ea4700580af05f5c20ab64f6)