Fix interactive query retry if LUKS2 unbound keyslot is present
If an unbound keyslot is present (e.g.. slot 0 usual slot, slot 1 unbound), the query loop could return ENOENT (keyslot not valid for segment) and this will stop epxected retry for slot quewry (--tries option).
If any previous slot rerutned EPERM (no valid passphrase), prefer this return code.