Comment 9 for bug 1746674

Reviewed: https://review.openstack.org/557622
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=461e42dcc4831083c46f4ff9763807862aab9b4a
Submitter: Zuul
Branch: stable/pike

commit 461e42dcc4831083c46f4ff9763807862aab9b4a
Author: Tetsuro Nakamura <email address hidden>
Date: Thu Feb 1 04:32:41 2018 +0900

    add check before adding cpus to cpuset_reserved

    There are some cases where None value is set to cpuset_reserved in
    InstanceNUMATopology at _numa_fit_instance_cell() function in
    hardware.py. However, libvirt driver treat cpuset_reserved value
    as an iterate object when it constructs xml configuration.

    To avoid a risk to get an error in libvirt driver, this patch adds
    a check to see if the value is not None before adding the cpus
    for emulator threads.

    Change-Id: Iab3d950c4f4138118ac6a9fd98407eaadcb24d9e
    Closes-Bug: #1746674
    (cherry picked from commit 24d9e06ec68dfd0ead9bc56ad186e7b4e0acd8fb)
    (cherry picked from commit 2dc4d7a366efe11acb1099eca13bd3f3c2af9012)