gpg: Fix error checking and improve error reporting.
* g10/gpg.c (check_user_ids): Differentiate between a second result and an error. If the key specification is ambiguous or an error occurs, set RC appropriately.
- Signed-off-by: Neal H. Walfield <neal@g10code.com>
- Reported-by: Werner Koch <wk@gnupg.org>
- Suggested-by: NIIBE Yutaka <gniibe@fsij.org>