Correctly handle restricted volumes in the Internet Archive

[ryanfb]

Restricted volumes, e.g. https://archive.org/details/womenslettersfro800bagn, should display the lock icon, like HathiTrust and Google Books do.

[ryanfb]

There's also "borrow"-able books, like this one: https://archive.org/details/introductiontogr00cros

Also in HT here: https://babel.hathitrust.org/cgi/pt?id=uc1.b4161701