Python executable path empty through rlm_python and rlm_python3

[Allie Hammond]

Hi!

Running sys.executable in a Python script run through either
rlm_python or rlm_python3 returns null - from what I can tell Python
normally gets this information from argv[0](usually passed by the OS)
and/or some environment variables.

I've confirmed this works fine when the python script is run on it's
own (not through FreeRADIUS).

Is this a bug or is there a way to configure this? I need it to be set
for a library we use.

Thanks!
-Allie