r175326 - Rework the visibility computation algorithm in preparation

[Rafael Espíndola]

> This is correct;  bar<foo2> is an implicit instantiation.  bar<foo2>::g()
> is an explicit specialization with an explicit attribute, and that should
> be enough to suppress the template-related restrictions.

Yes, TNorthover just pointed that to me on IRC. I guess we should just
not call getLVForDecl on the class when we have an explicit
specialization of a member of a class template. It would look just for
the template arguments, but we want to ignore them.

> John.

Cheers,
Rafael