Invalid keys when switching smartcard from ed25519 to other curves

[Trevor Bentley]

> I see the problem.  I think that it is the call of ask_curve from
> ask_card_keyattr in card-util.c.  Isn't it?
> 
> (Looking your patch with the context of keygen.c, I didn't understand
> why ask_curve matters.)

Yes, exactly, it's the call in ask_card_keyattr() that is a problem.  It 
gets 'stuck' on the EdDSA algo ID when it passes in the current curve 
parameters.

Thanks,

Trevor