Make sure the Lightroom is up-to date. The dehaze slider will be under the effect panel. Also make sure the camera process version is 2012(current). You can check that in the camera calibration panel.
Finally - ensure that you're opening Lr CC and not some earlier version of Lr on your machine. That's caught quite a few folk out.
I don't know what the problem was but I uninstalled LR CC and the rebooted my PC then I reinstalled LR CC. And now everythis is there and works as advertised.