What Yoni said is correct. At one time, you couldn't get email, but now LinkedIn is doing an odd hybrid of OAuth 1.0a along with OAuth2-style scoped permissions. If you ask for "r_emailaddress" permission in the scope parameter during authorization, you can get the email address.
But Yoni is also correct in saying that this is not yet supported. It's something that I've had on a backburner for awhile now, but I've got higher priority items to address first (specifically, Spring Social/Spring Security integration, automatic token renewal, etc).
To address this, there's probably more to do than just add it back to the LinkedIn API binding. We'll also need to make sure that Spring Social Core's OAuth 1.0a will support non-standard authorization parameters so that the scope parameter can be sent. I'm reluctant to directly support the scope parameter in OAuth 1.0a code, because scope isn't a standard parameter. But I'm open to supporting arbitrary parameters, of which scope could be one.
Hang tight and I'll get to it. Of course, if someone reading this is interested in helping out, I always welcome pull requests.
Spring Social Project Lead