Fix test broken by early cherry pick of f087a6f

f087a6f77ef was cherry picked to stable/icehouse but hadn't
landed yet when it was needed, so we pulled it in while
it still had only one +2 in Gerrit.  Unfortunately another
change was merged since then that causes problems: a unit test
fails because it needs a similar update to what was done in
f087a6f77ef (which will probably now need to be rebased
and have this patch applied before it can actually land upstream).

This patch makes a minor correction to a unit test that is inline
with f087a6f77ef to get tests passing again.

Related-Change-Id: Iec329d1c12a48ea90ba9d57decd0996fde6544f0
Closes-Bug: #1305423
Upstream-review: https://review.openstack.org/#/c/100362/