README: Remove the notice it was not used yet in production, after I got 2 user feedbacks.
README: Remove the notice it was not used yet in production, after I got 2 user feedbacks.

sean-/libvmod-throttle,nand2/libvmod-throttle,asalem/libvmod-throttle,sean-/libvmod-throttle,varnish/libvmod-throttle,nand2/libvmod-throttle,jennytoo/libvmod-throttle,varnish/libvmod-throttle,asalem/libvmod-throttle,jennytoo/libvmod-throttle