Investigate a warning on running tox

[hongbin]

I followed the dev-quickstart guide (https://github.com/stackforge/magnum/blob/master/doc/source/dev/dev-quickstart.rst) on Ubuntu14.04. When I run the tox command, it gave me a warning. We need to investigate the cause of this warning and disable it if it can be ignored.

$ tox -evenv -- echo 'done'
venv create: /home/ubuntu/magnum/.tox/venv
venv installdeps: -r/home/ubuntu/magnum/requirements.txt, -r/home/ubuntu/magnum/test-requirements.txt
venv develop-inst: /home/ubuntu/magnum
venv runtests: commands[0] | echo done
WARNING:test command found but not installed in testenv
  cmd: /bin/echo
  env: /home/ubuntu/magnum/.tox/venv
Maybe forgot to specify a dependency?
done

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/153763
Committed: https://git.openstack.org/cgit/stackforge/magnum/commit/?id=561f12c79f86262fd5d6ce0282176f779acd5669
Submitter: Jenkins
Branch: master

commit 561f12c79f86262fd5d6ce0282176f779acd5669
Author: Davanum Srinivas <email address hidden>
Date: Fri Feb 6 23:17:09 2015 -0500

    Change command for creating a virtualenv

    echo "Done" seems to give people the wrong impression that
    something went wrong. Just run python -V to print the python
    version instead.

    Closes-Bug: #1412223
    Change-Id: I72d47fd2f1bf99ea13047598ead5df0fe8fa42ff