g10: Be more careful when checking if a binding is signed by a UTK.
* g10/tofu.c (signed_by_utk): When checking if a key is signed by an ultimately trusted key, only consider the signatures on the specified user id. * tests/openpgp/tofu.scm: Add test for the above.
- Signed-off-by: Neal H. Walfield <neal@g10code.com>