bshaffer/oauth2-server-php — pull request #174 by trickleup (2013-06-28 18:56:51+00:00)
Title: make user_id not required for refresh_token grant

Same as issue #167 and PR #168 but for refresh_token grant.

`OAuth2_Storage_RefreshTokenInterface::getRefreshToken()` does not require `user_id` to be returned, but `RefreshToken::getUserId()` expects it to be set in the refresh_token data fetched from storage.