Pinning tox to version 2.1.1.
Pinning tox to version 2.1.1.

This is a temporary workaround due to the config parsing
change introduced in 2.2.0.

See #339 for more details.

googleapis/oauth2client,google/oauth2client,clancychilds/oauth2client,jonparrott/oauth2client,google/oauth2client,clancychilds/oauth2client,googleapis/oauth2client,jonparrott/oauth2client