gpgv: Initialize compliance checker.

* g10/gpgv.c (main): Call gnupg_initialize_compliance.

The compliance checker needs to be initialize so that it won't let
spit out a "not suitable" message. We use the module name of gpg.
Because there is no option to change the compliance mode in gpgv we
will always be in the default (CO_GNUPG) mode. It also does not make
much sense to have it here because gpgv expects a "curated" keyring.

• GnuPG-bug-id: T3404
• Signed-off-by: Werner Koch <wk@gnupg.org>