install_change_id_hook told a framework that already declares the change-id script "was not installed" and to go add it -- the same latent copy of 3mum4e67kbd2n flagged in the stack create fix. It now reads clients/git::hooks::declared too, via a new Installed::describe_given, and reports the hook as already in place instead. Change-Id: Ic8363c26e3b1735b6f10182f275e9326026267ff