We currently assume we are deploying ironic with the rest of
a cloud and assert that glance/neutron/nova are enabled. This
makes it a bit more flexible and allows deploying with only
the minimum required services if desired, and asserts the others
are enabled when we intend on testing nova+ironic integration.
This is required for in-tree python-ironicclient functional tests,
which we aim to run against a minimal devstack deployment.
Change-Id: I99001d151161fa225b97c3ba6b167a61aa9b59fe
de77c471f3