Error when no refresh_token is available

[espen]

Mailchimp only uses access_token and does not give a refresh_token. Currently it seems like omniauth-oauth2 requires refresh_token as it will check for it when access_token is assumed to be expired.

I have set option :auth_token_params, {:expires_at => 10.minutes.from_now} to avoid this but it seems like not the best solution. Is there any way to tell omniauth-oauth2 that no refresh_token should be expected? Or perhaps this could be added as an option on the strategy instead of setting expiry?

See stevenkaras/omniauth-mailchimp#8

[espen]

Sorry, duplicate of #143