Why?

What I always do is that I git clone the upstream repo. I call that remote "origin" no matter if I have SSH access to it or not. 
Then, only when I have a branch ready that is different from `origin/master` do I fork a the repo. 

I know it's a personal choice/taste but by making origin == upstream that means it's easier to track master. Otherwise you'd have to do: ``git fetch mozilla-repo; git checkout master; git merge mozilla-repo/master`` or something like that that is just confusing.