Unable to execute tox -e pep8

[yangweiwei]

Traceback (most recent call last):
  File "/usr/bin/tox", line 9, in <module>
    load_entry_point('tox==1.9.0', 'console_scripts', 'tox')()
  File "/usr/lib/python2.7/site-packages/tox/_cmdline.py", line 26, in main
    config = parseconfig(args, 'tox')
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 42, in parseconfig
    parseini(config, inipath)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 307, in __init__
    self._makeenvconfig(name, section, reader._subs, config)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 370, in _makeenvconfig
    vc.commands = reader.getargvlist(section, "commands")
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 569, in getargvlist
    commandlist.append(self._processcommand(current_command))
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 609, in _processcommand
    argv = list(shlexer)
  File "/usr/lib64/python2.7/shlex.py", line 270, in next
    if token == self.eof:
  File "/usr/lib64/python2.7/shlex.py", line 96, in get_token
    raw = self.read_token()
  File "/usr/lib64/python2.7/shlex.py", line 172, in read_token
    raise ValueError, "No closing quotation"
ValueError: No closing quotation

[yangweiwei (496176919-6)]

I have do some change to it, see https://review.openstack.org/#/c/454455/