scd: New getinfo subcommand "dump_state".
* scd/command.c (cmd_getinfo): Add subcommand. Always init CTRL for simplicity.
A state dump looks like
app_dump_state: card=0x00007f1b38017c90 slot=1 type=yubikey refcount=1 app_dump_state: app=0x00007f1b38018100 type='openpgp' app_dump_state: app=0x00007f1b3800cb70 type='piv' app_dump_state: card=0x00007f1b38013a10 slot=0 type=gnuk refcount=0 app_dump_state: app=0x00007f1b38016fc0 type='openpgp'
and can also be triggered by a SIGUSR1. This explicit command allows
to dump the state also on Windows. Use for example
gpg-connect-agent 'scd getinfo dump_state' /bye