Deprecate Ironic compute driver and sched manager

Updates the Ironic compute driver and scheduler manager so that they
subclass the now in-Nova-tree driver classes. This should de-duplicate
code maintenance across Nova and Ironic and also provide end users
an easier upgrade path (with Deprecation log messages).

This patch also removes the old Ironic compute driver tests and classes
since those now live in Nova.

This patch also removes a line from tox.ini which was copying the second
set of unit test outputs; those no longer exist, since we are no longer
running unit tests on nova code in this tree.

Co-Authored-By: Dan Prince <dprince@redhat.com>
Co-Authored-By: Devananda van der Veen <devananda.vdv@gmail.com>

Change-Id: Ic194f779eca470e4a4dd8a3fbd31ca5a6f6b4f7e
Merge "Deprecate Ironic compute driver and sched manager"