kbx: Change return type of search functions to gpg_error_t.
* kbx/keybox-search.c (keybox_search_reset): Change return type to gpg_error_t. (keybox_search): Ditto. Also handle GPG_ERR_EOF. * sm/keydb.c (keydb_search_reset): Ditto.
- Signed-off-by: Werner Koch <wk@gnupg.org>