Nothing wrong with calling the dog, Nigger, in my opinion. It is a word of its time and the time was the 1940's.
Having worked with quite a few black people in my working life, they tend to call each other 'nigger' anyway. If you watch films featuring black actors, it's written into the script as a matter of course. For realism or basically because they damn well can and get away with it.
I don't think that many people would actually give a about the use of the word in the new film as most normal, non-anally retentive human beings know that it's the name of a f*****g dog! Also if they were really that worried about it, surely they would have had it removed from the original 50's film.
Jeez these people are so chuffing thick it frightens me. And we allow them to roam free in our society. PCism has gone too far now and if anyone starts to give me the 3rd degree about being a bit non-PC, well, get knotted (that's polite) and go very far away. I don't want to be infected by your stupidity.
Get a grip.