Actually, the passive nerf has been reverted. Some of the changes that are made to champions are done in a way that aren't easily detected by the scraping tools that Surrender@20 and other similar sites, so that's why you may not see them as reverted in those daily updates. In the case of Skarner's passive, the only way to actually check (except for internally here at Riot) its effects is in-game.
To make sure I was right on this, I just checked on our internal WIP patch notes source, as well as personally checking the files in-game, and the nerfs do appear to be reverted. I haven't actually checked on PBE, but I would expect that if you logged in to PBE and played a game, you would notice that his passive is the same as on Live. I think the only changes you'd see are a nerf to his ult AD ratio and removal of the 6-target cap on his E.