Some quick information that if you have LR 6 standalone and update to LR 6.1 then one can still use the Dehaze effects.
Although the 'slider' doesn't appear in the Effects tab one can use develop presets as a work around.
Prolost has a set of free presets one can use but it's easy enough to 'roll your own' if you open one of these free presets with a text editor and emulate the settings.
Works like a charm.
I was somewhat 'miffed' that LR6.1 didn't include the Dehaze update so though it might be useful information to others.
P.S. I have no 'association' with the Prolost website (they also sell some presets) - just in case anyone might think so