access: fix po_check when polkit is disabled

access: fix po_check when polkit is disabled

The generated org.libvirt.api.policy.in file was recently added to the
POTFILES list as it contains translatable messages.

It is only generated when WITH_POLKIT && WITH_LIBVIRTD is satisfied
though, resulting in the 'po_check' syntax rule failing if either of
those conditions are not met.

It is harmless to unconditionally generate this file, as a separate
rule takes care of of installing it, and the latter remains under
the build conditions.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>