Show terms and privacy policy if FxA is enabled (bug 1033851)

Add the terms and privacy policy links on create-pin if FxA is enabled (based on the data attr)

![firefox_os_simulator](https://cloud.githubusercontent.com/assets/1514/3937583/10baacec-24af-11e4-9acc-b383b8874fdb.png)

It gets dismissed as soon as you type a char or cause an error (so there's room for the error).


what happens in the trusted UI when they tap on the terms? Is there a back button? If you added ``target="_blank"`` to the links then they would open in the browser app. The user would have to navigate back to the Marketplace but that might be better, I don't know.