Shrink tox.ini to the new short version.
Fix the test cases to be able to be run in nosetets plus the
openstack.nose_plugin, which finally removes the need for
nova/testing/runner.py
Also, now we'll just output directly to stdout, which will
make nose collect the trace logging directly and either output
it at the end of the run, or inject it into the xunit output
appropriately.
Change-Id: I1456e18a11a840145492038108bdfe812c8230d1