ellipsoidal halo analysis is broken

[brittonsmith]

Issue #1245

Originally reported by: Britton Smith (Bitbucket: brittonsmith, GitHub: brittonsmith)

The ellipsoidal halo analysis example in the docs does not work. It appears to be a simple a units error that can probably be fixed easily. That said, this code is untested and only exists within the yt-2.x era halo finding framework. This function needs to be ported into a recipe or callback function that works with the HaloCatalog if it's going to be usable. For now, I am going to leave a note in the docs that it is currently broken.