successful import.
* keydb.c (keydb_set_ephemeral): New.
(keydb_store_cert): New are ephemeral, changed all callers.
* keylist.c (list_external_cb): Store cert as ephemeral.
* export.c (gpgsm_export): Kludge to export epehmeral certificates.
* gpgsm.c (main): New command --list-external-keys.