scd: Factor common PIN status check out.
* scd/iso7816.h (ISO7816_VERIFY_ERROR): New. (ISO7816_VERIFY_NO_PIN): New. (ISO7816_VERIFY_BLOCKED): New. (ISO7816_VERIFY_NULLPIN): New. (ISO7816_VERIFY_NOT_NEEDED): New. * scd/iso7816.c (iso7816_verify_status): New. * scd/app-nks.c (get_chv_status): Use new function.
Backported from master:
- Removed the non-existant app-piv.c patches.
- Signed-off-by: Werner Koch <wk@gnupg.org>