Missing Python Tab - iPython failed

I've had this error where I don't have the Python tab in FaceFX Studio, but it only seems to affect some people, especially me. So I did some digging and found the solution.

It turns out iPython is looking for the "HOME" directory from environment variables. Either HOME, or HOMEDIR + HOMEPATH, which probably makes sense, but for whatever reason our network administrator has set our HOMEDRIVE env variable to Z:\ which maps to a user folder on the network drive. (I guess this is so our user profile is shared across the network... or it was a mistake...) However, we don't have access to modify this folder. So iPython finds that path, and it's a valid path, and then later uses it but fails because it doesn't have write access to make directories there.

I thought I'd share it in case other people are missing the Python tab.
The tell-tale sign was this error in the log, which was unusal that it was trying to access my Z:\

File "C:\Program Files (x86)\FaceFX\FaceFX 2017\Python27\python27.zip\os.py", line 157, in makedirs
mkdir(name, mode)
WindowsError: [Error 5] Access is denied: u'Z:\\_ipython'

22:32:09: Error: Error executing Python script.
22:32:09: Error: Command Failed: exec -f ipython.py;

It might work to change my HOME directory env variables, but I'm a bit cautious to do this without validating it with IT first, so, I did a quick fix on to just return "C:\\" if it fails. Which is what it does if does as a last resort for most Windows systems. If the issue remains I'll do a better job on that fallback. :)
IPython\genutils.py line 942