agent: Fix regression for access through the extra secket.
* agent/command.c (cmd_keyinfo): Allow KEYINFO command for one key. (cmd_scd): Allow SCD command to invoke GETINFO, GETATTR, and KEYINFO --list=encr sub commands.
- GnuPG-bug-id: T5063
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>