scd:p15: Fix decrypt followed by sign problem for D-Trust cards.
* scd/iso7816.c (iso7816_select_mf): New. * scd/app-p15.c (card_product_t): New. (struct app_local_s): Add field 'card_product'. (read_ef_tokeninfo): Detect D-Trust card. (prepare_verify_pin): Switch to D-Trust AID. (do_decipher): Restore a SE for D-TRust cards. Chnage the passing indicator to 0x81.
Using what I learned from a USB trace running the Governikus Signer
Software on Windows this fixes the left over problem with the new
D-Trust card support.
- Signed-off-by: Werner Koch <wk@gnupg.org>