javier hernandez scored twice to make it six goals in eight games for real .
carlo ancelotti says striker 's form makes him ` non-negotiable ' at present .
hernandez is enjoying his football at present despite uncertain future .
real madrid 's win moved them back to within two points of barcelona .
read : celta vigo 2-4 real madrid : javier hernandez scores twice as real come from behind to keep la liga title battle with barcelona alive .