dirmngr: ADNS error handling fix.
* dirmngr/dns-stuff.c (resolve_name_adns, get_dns_cert, get_dns_cname): Use gpg_error and gpg_err_code_from_errno to compose the error value.
This fixes commits 6f1d8123d61b3efac94b4c61ee75bd947790ba42.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>