scd,agent: Improve the OpenPGP PIN prompt texts.
* scd/app-openpgp.c (get_prompt_info): Change texts. * agent/call-pinentry.c (struct entry_features): New. (getinfo_features_cb): New. (start_pinentry): Set new fucntion as status callback. (build_cmd_setdesc): New. Replace all snprintf for SETDESC by this one.
- Suggested-by: Andre Heinecke
- Signed-off-by: Werner Koch <wk@gnupg.org>