Comment 2 for bug 1817542

Reviewed: https://review.openstack.org/639936
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=31fe7c76009e1c6d7859036e44b057d081b059b5
Submitter: Zuul
Branch: master

commit 31fe7c76009e1c6d7859036e44b057d081b059b5
Author: Takashi NATSUME <email address hidden>
Date: Thu Feb 28 13:49:41 2019 +0900

    Fix an error when generating a host ID

    When instance action events are created by periodic tasks,
    the project IDs of them become null (None).
    It causes an error when 'hostId' is generated
    in the "Show Server Action Details"
    (GET /servers/{server_id}/os-instance-actions/{request_id})
    API.

    Fix the issue by using the project ID of the server
    if the project ID of the event is None.

    Change-Id: Iac07fcddd4cc3321c6efe702066eb8af6a875418
    Closes-Bug: #1817542