These had previously had default settings set. 

From @khandelwal "Please don't set the defaults in settings.py. Those are not meaningful to someone else that's running our code. It's better to set them as blank here, and expect that they will be over-ridden in local_settings.py."

Good to know. I will add documentation on this along with the default values that were there before so that we don't have to think too much about it if the exact version isn't applicable to our task.