gpg: Change out of core error message.

* g10/tofu.c (fingerprint_str): Die with the error code returned by
the failed function.
(time_ago_str): Ditto.  Do not make a comma translatable.
(fingerprint_format): Use "%zu" for a size_t.

Also wrapped some long strings.

In general we should not use log_fatal or use xmalloc functions but
properly return an error code and use xtrymalloc like functions.

• Signed-off-by: Werner Koch <wk@gnupg.org>