agent: Allow signing with card key even without a stub key.
* agent/call-scd.c (agent_card_serialno): Allow NULL for R_SERIAL. (struct readkey_status_parm_s): New. (readkey_status_cb): New. (agent_card_readkey): Add optional arg R_KEYREF and change all callers. * agent/findkey.c (key_parms_from_sexp): Allow also a "public-key". * agent/divert-scd.c (ask_for_card): Allow for SHADOW_INFO being NULL. * agent/pksign.c (agent_pksign_do): Fallback to sign with an on-card if there is no stub key yet. Create the stub key. Also fixed a misnaming between s_pkey and s_skey.
This change allows to create OpenPGP keys directly from a card without
first making sure that a stub key exists. It is also the less
- Signed-off-by: Werner Koch <firstname.lastname@example.org>