Comment 9 for bug 1423952

The thinking is https://review.openstack.org/#/c/130601/ introduced the bug since _do_build_and_run_instance is passed args rather than kwargs and since that's in a separate thread we lose the error.

Note that change was backported to stable/juno and stable/icehouse, so it's also there:

https://review.openstack.org/#/q/Ife712c43c5a61424bc68b2f5ab47cefdb46ac168,n,z

And we need to backport the fix.