gpg: Fix misleading log message when checking regexp.

* src/trustdb.c (check_regexp): Correctly print whether the
regexp matched or not.

This patch fixes the log message displayed when gpg attempts to
match the regexp associated with a trust signature with an user ID.
The current message interprets the 'ret' variable backwards, and
displays 'YES' when the regexp actually fails to match.

• Signed-off-by: Damien Goutte-Gattat <dgouttegattat@incenp.org>