Comment 8 for bug 1780727

Reviewed: https://review.openstack.org/583566
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=0be8cbc302aa77b312e031f6a7a419e83afd6e3b
Submitter: Zuul
Branch: stable/queens

commit 0be8cbc302aa77b312e031f6a7a419e83afd6e3b
Author: Matt Riedemann <email address hidden>
Date: Fri Jul 13 15:42:03 2018 -0400

    Handle HostMappingNotFound when deleting a compute service

    If the compute service we're deleting has never been
    discovered (mapped to a cell using discover_hosts) or the
    host mapping was already deleted, we need to handle the
    HostMappingNotFound error when deleting a compute service
    so that we (1) don't 500 out of the API and (2) continue to
    delete the compute service.

    Change-Id: I0d7644db3537a67b94e75972b3c4fce25a623763
    Closes-Bug: #1780727
    (cherry picked from commit ee6e0c1e7eb861e56915c5b6c60a214b75240366)