Skip verifying empty devices in test_tagged_attachment until bug is fixed

We have a non-trivial amount of failures due to bug 1775947 [1]
and so far attempts at debugging the issue haven't proved
fruitful, so let's skip the last (problematic) portion of the
test until we can get a recreate with proper debug to help
isolate the problem.

Related nova debug patch: https://review.openstack.org/584032

[1] http://status.openstack.org/elastic-recheck/#1775947

Change-Id: I3104041cb66f912727aabd6c5894600dc87a1229
Related-Bug: #1775947
1 file changed