Always provide refresh token, whether access token expires or not

[RKushnir]

I found this line that only exposes the refresh token if the access token has an expiration time

omniauth-oauth2/lib/omniauth/strategies/oauth2.rb

Line 41 in 01fbfb5

hash["refresh_token"] = access_token.refresh_token if access_token.expires? && access_token.refresh_token

My problem is, Twitch OAuth has expiring access tokens, but they don't tell you when the token is going to expire(access_token.expires? returns false). So you would want to keep the refresh token and use it whenever that expiration happens.

I wonder why this condition was added, is it to conform to some spec? And can we remove it to always provide the refresh token?