Find Missing Kwargs script doesn't check all files

[Thetwam]

When reviewing #455, I discovered that scripts/find_missing_kwargs.py is now finding missing **kwargs in enrollment.py. There is no difference between that file on the issue branch and on develop, yet the script finds the error only in the issue branch.

This behavior occurs both in Travis and when I run the script manually on my local environment.

It looks like the problem starts early on in the script:

for _, module in inspect.getmembers(canvasapi, inspect.ismodule):

If I replace _ with module_name and print out the name immediately after, the list of modules is considerably shorter than expected. I suspect it's related to some shenanigans with imports and how we set up the canvasapi module.