superuser: Fix incorrect disabled property
superuser: Fix incorrect disabled property

`disabled` property had no effect.

martinpitt/cockpit,deryni/cockpit,cockpit-project/cockpit,garrett/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,garrett/cockpit,garrett/cockpit,mvollmer/cockpit,garrett/cockpit,deryni/cockpit,deryni/cockpit,deryni/cockpit,deryni/cockpit,martinpitt/cockpit,deryni/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,garrett/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,deryni/cockpit,cockpit-project/cockpit