* scd/app-openpgp.c (struct app_local_s): Add keygrip_str.
(store_keygrip): New.
(read_public_key): Store the keygrip.
(get_public_key): Sitto.
(send_keypair_info): USe the stored keygrip.
(check_keyidstr): New.  Factored out from other functions and
extended.
(do_sign): Use check_keyidstr.
(do_auth): Ditto.
(do_decipher): Ditto.
(do_check_pin): Ditto.