[Extractor] Add Finding Win 7z Path via Registry

Instead of creating the list `win_7z_exes[...]`, you should insert `win_7z_path` into the existing list which should be returned to it's original position above the try..except. https://docs.python.org/2/tutorial/datastructures.html#more-on-lists

Sometimes that's the way of things but it's your code idea that you are submitting and it means future code you submit will be more polished because we offered guidance on the changes required here.