scd: Make SERIALNO --all work correctly and use it.
* scd/app.c (maybe_switch_app): Factor reselect code out to ... (run_reselect): new. (app_write_learn_status): Tweak diagnostics. (app_do_with_keygrip): Run reselect if a card has more than one switchable application. * agent/call-scd.c (agent_card_serialno): Ditto. * tools/card-call-scd.c (start_agent): Use option --all with SERIALNO. (scd_serialno): Ditto.
- Signed-off-by: Werner Koch <wk@gnupg.org>