This is clearly not an own goal, but the goal should be attributed to Lavezzi.
I really can't undestand why they didn't, and most of all I can't understand why noone even mentioned it at least.
As far as I know, an own goal is given when the defending players deviates a ball that wouldn't have gone in the direction of the goal (i.e. if there wasn't anyone, and the shot would be in the goal, that's not an own goal)
It seems pretty clear to me that in this case if David Luiz wasn't there the free kick from Lavezzi would have gone directly in the goal.
https://www.youtube.com/watch?v=Kmgk0eGNxhY