gpg: Change TOFU_STATS to return timestamps.
* g10/tofu.c (write_stats_status): Add arg FP to print a colon formated line. Adjust for changed TOFU_STATS interface. (show_statistics): Let the query return timestamps and use gnupg_get-time to compute the "time ago" values.
- Signed-off-by: Werner Koch <wk@gnupg.org>