tox fails to run on tripleo-common with tox.ConfigError: ConfigError: No support for the tty substitution type

Introduced with https://review.opendev.org/#/c/663336/31/tox.ini

$ tox -e py36
Traceback (most recent call last):
  File "/home/aschultz/.pyenv/versions/3.6.2/bin/tox", line 11, in <module>
    sys.exit(run_main())
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/session.py", line 40, in run_main
    main(args)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/session.py", line 45, in main
    config = prepare(args)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/session.py", line 27, in prepare
    config = parseconfig(args)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 271, in parseconfig
    parseini(config, inipath)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 838, in __init__
    config.envconfigs[name] = self.make_envconfig(name, section, reader._subs, config)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 866, in make_envconfig
    res = meth(env_attr.name, env_attr.default, replace=replace)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1062, in getargvlist
    return _ArgvlistReader.getargvlist(self, s, replace=replace)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1247, in getargvlist
    commands.append(cls.processcommand(reader, current_command, replace))
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1278, in processcommand
    new_word = reader._replace(word)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1108, in _replace
    replaced = Replacer(self, crossonly=crossonly).do_replace(value)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1141, in do_replace
    expanded = substitute_once(value)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1139, in substitute_once
    return self.RE_ITEM_REF.sub(self._replace_match, x)
  File "/home/aschultz/.pyenv/versions/3.6.2/lib/python3.6/site-packages/tox/config.py", line 1179, in _replace_match
    "No support for the %s substitution type" % sub_type)
tox.ConfigError: ConfigError: No support for the tty substitution type