Comment 4 for bug 1645479

Reviewed: https://review.openstack.org/404496
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c3f0f2ebc1b8b3b8c6bf8a596df62063519a0844
Submitter: Jenkins
Branch: stable/newton

commit c3f0f2ebc1b8b3b8c6bf8a596df62063519a0844
Author: Matt Riedemann <email address hidden>
Date: Mon Nov 28 16:45:58 2016 -0500

    Fix expected_attrs kwarg in server_external_events

    The Instance.get_by_uuid method takes an expected_attrs
    kwarg which needs to be a list or tuple, not just any old
    iterable like a string. Because of how the underlying
    Instance object code massages this value, it's not a hard
    failure but does mean you don't join the columns you expect
    when getting the instance.

    This makes it a list and makes sure the stub in the unit
    tests is checking for valid values.

    Change-Id: I3ad85f9062b5cb19962d9e6a7af52440166def45
    Closes-Bug: #1645479
    (cherry picked from commit cbcff11b6a206a58093017fb9471d818d484ca34)