Comment 9 for bug 1716903

Reviewed: https://review.openstack.org/503601
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=062f5b2e876a09119e43c1905f91610cd4e5d015
Submitter: Jenkins
Branch: master

commit 062f5b2e876a09119e43c1905f91610cd4e5d015
Author: Yikun Jiang <email address hidden>
Date: Wed Sep 13 19:35:49 2017 +0800

    Add @targets_cell for live_migrate_instance method in conductor

    With microversion < 2.34, the API casts to the migrate_server
    method in super conductor which targets the context using the
    @targets_cell decorator.

    With microversion >= 2.34, the API casts to the live_migrate_instance
    method in super conductor which does not use the @targets_cell
    decorator, which results in a failure to lookup the instance action
    record when recording the start of the action event with the
    @wrap_instance_event decorator.

    This change simply adds the decorator and provides a test which
    was missing for this before. Note that the live migration CI job
    didn't catch this regression since it only tests up to microversion
    2.26.

    Co-Authored-By: Matt Riedemann <email address hidden>

    Closes-bug: #1716903
    Change-Id: I21d3f3b7589221b7e0a46c332510afc876ca5a79