configure.ac: remove users tools detection
configure.ac: remove users tools detection

207cc8bf5b020f9969b2f78ca0ea61519f3da159 removed the last user of these
but forgot to clean it up in configure.ac.

martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mvollmer/cockpit