Access Token refresh broken

[denic]

Hi, I encountered an error that gives me a really weird error message from PayPal (http://stackoverflow.com/questions/38603625/paypal-java-future-payment-obtain-refresh-token).

It looks like they updated their API and now the access token refresh does not work any longer.

Also I already fixed it, I did not submit a pull request because I accidentally committed my mix.lock, that you may not want to have in your repo and I do not want to pollute your commit history. But you can find my changes here:

https://github.com/denic/pay/commit/75160aedec6f3c0fe56e9972caeaf9b9fdbae601

[era]

Hello Denic,

Thank you again for it. I cherry-pick your commit: 1d1f798

Thank you! :)