Per clarkb, should any step in pre.yaml fail, zuul presently retries
the entire job up to the built in retry limit which cannot be changed
or disabled on a job basis. In the terms of setting up devstack, this
is not ideal as devstack is not perfect and can often fail for unrelated
reasons such as package mirrors being updated or even another project
or component failing to setup properly.
As such, in order to be good neighbors and minimize the amount of
time it takes to troubleshoot such issues, we need to move the
devstack setup into the main part of the CI job.
Change-Id: I08d6f3132ebc045ba7e2d1295efe39af7c57187c
Julia Kreger