Comment 2 for bug 1724121

Reviewed: https://review.openstack.org/512464
Committed: https://git.openstack.org/cgit/openstack/qinling/commit/?id=eaa667d4df99af853b36a8d137b57e7831fcffbe
Submitter: Zuul
Branch: master

commit eaa667d4df99af853b36a8d137b57e7831fcffbe
Author: junboli <email address hidden>
Date: Tue Oct 17 10:38:04 2017 +0800

    Fix 'cover' tox job fails for option --coverage not recognized

    When running command tox -ecover, tox job will fail. the error message is

    ======================================================================
    FAIL: process-returncode
    tags: worker-0
    ----------------------------------------------------------------------
    returncode 1
    Ran 733 (+17) tests in 856.852s (+164.804s)
    FAILED (id=6, failures=2, skips=7)
    error: testr failed (1)
    ERROR: InvocationError: '/home/github/mistral/.tox/py27/bin/python setup.py test
    _____________________________________________________ summary __________________
    ERROR: py27: commands failed

    Change-Id: I21a335992683aa94d2cf47c4a4fc0f43849dec9a
    Closes-bug: #1724121