Fix issue #4416

Fix opengraph and and oembed issues #4987 & #4416 
This causes some tests to fail. Error is :

    Failure/Error: post_params = @service.create_post_params(post)
        Double received unexpected message :urls with (no args)

I guess somehow I should put `urls: ` in [this expression](https://github.com/diaspora/diaspora/blob/develop/spec/models/services/facebook_spec.rb#L36) but I don't know how.