certdb/Main: update "acme" usage text after c3c56e77947f08186d4adf51b6802f4e3fa5ca8b
certdb/Main: update "acme" usage text after c3c56e77947f08186d4adf51b6802f4e3fa5ca8b

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy