Comment 6 for bug 1564921

Reviewed: https://review.openstack.org/375715
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=97d784b454baf3289ce2f3e1812fb94c8469b136
Submitter: Jenkins
Branch: stable/newton

commit 97d784b454baf3289ce2f3e1812fb94c8469b136
Author: Vladyslav Drok <email address hidden>
Date: Thu Apr 14 21:15:10 2016 +0300

    Update instance node on rebuild only when it is recreate

    When using ironic virt driver, if scheduled_node is not specified
    in rebuild_instance compute manager method (as it happens in case
    of instance rebuild), the first ironic node is selected:

     computes = ComputeNodeList.get_all_by_host(context, host, use_slave)
     return computes[0]

    After the first rebuild, instance.node is updated to be this first
    ironic node, which causes subsequent rebuilds to fail, as virt driver
    tries to set instance_uuid on a newly selected ironic node and fails.

    Closes-bug: #1564921
    Change-Id: I2fe6e439135ba6aa4120735d030ced31081ef202
    (cherry picked from commit 54b122caec1ae2418fc3e296be604d072cb5815a)