There are potentially two related issues here which can result in
an empty generated groups file. The first is that if there are OS_
environment variables set, then os-client-config can create an 'environ'
cloud. That cloud then, in most cases here, will not be a valid cloud
since it won't be a full config, so iterating over all existing clouds
to get their server will fail, meaning that the inventory will be empty
meaning that generated groups will then be generated empty.
To deal with that, we can consume the newer upstream option that allows
the inventory to not bail out if it has a bad cloud, but instead get all
of the resources from the clouds that do work.
Additionally though, we can do an explicit inventory run so that we can
look to see if the inventory run failed, and if so, avoid running the
expand-groups.sh script, since we'd be fairly assured that it would be
running on top of a bad inventory cache.
Change-Id: Ib18987b3083f6addc61934b435d7ecb14aa1d25a
3b9eda9359