Packaging Tox for OPenstack unit tests

[Adam Young]

It  seems like the use of nose is diverging from what the CI team is 
doing.  According to Monty Taylor:


<mordred> ayoung: the CI system uses tox and does not use run_tests or 
with_venv for anything - this has been the case for almost a year now
<mordred> ayoung: we've been doing our best to remove chunks of code 
like run_tests.py that are just copied amongst all of the projects and 
all of the branches of the projects

Currently, the Keystone unit test code is broken due to running:

  tools/with_venv.sh nosetests
  Failure: ImportError (No module named keystone.common) ... ERROR


And, while we will deal with this straight away, it looks like the 
correct longish solution is to use Tox instead of nosetests.

Any plans to package this?  Should we push to make Tox part of the core 
Fedora distro, or is there some argument against?