* scd/app-openpgp.c (do_change_pin): Allow prefixing the CHVNO with
"OPENPGP."
* tools/card-call-scd.c (scd_change_pin): Change API to use strings.
* tools/gpg-card-tool.c (cmd_passwd): Adjust for change.
(cmd_unblock): Ditto.
--
The generic keyref allows for better error detection in case a keyref
is send to a wrong card.
Signed-off-by: Werner Koch <wk@gnupg.org>