scd: Cleanup SERIALNO protocol.
* scd/app.c (app_get_serial_and_stamp): Remove. (app_get_serialno): New. (app_write_learn_status): Use send_status_direct. (app_getattr): Use app_get_serialno for SERIALNO and send with send_status_direct. * scd/app-openpgp.c (do_getattr): Likewise. * scd/command.c (cmd_serialno): Don't send TIMESTAMP of 0. (cmd_learn): Likewise. Don't inquire with TIMESTAMP of 0.
In the SERIALNO protocol, timestamp used to be considered, but had never
used at all. In the new implementation, removed card/token is always
detected and connection becomes invalid, no timestamp is required any
more. Examined scute and poldi as well for this protocol change.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>