ES-config enters uninterruptible sleep on exit

Tested with both the latest RetroPie setup and associated disk image. Since the ES-config setup script pulls from the github, it should be current.

Steps to reproduce:

1. Fresh install of RetroPie as above.
2. Place ES-config folder into ~/RetroPie/supplementary if not present (this to fix the "script error" on save)
3. Launch ES-config from emulationstation
4. Attempt to configure RetroArch and/or Gngeo controls (using SNESdev controllers)
5. Save controller settings successfully
6. Quit

At this point, es-config should be in an uninterruptible sleep state D+:

 2982 tty1     S+     0:00 emulationstatio
 2986 tty1     Sl+    0:21 emulationstatio
 2992 tty1     S+     0:00 sh
 2993 tty1     S+     0:01 python3
 2994 tty1     S+     0:00 sh
 2995 tty1     D+     1:13 es-config

It can't even be rebooted like this. I think this is also preventing me from configuring controls for RetroArch/gngeo emulators.

Completes normally when run directly:

cd ~/RetroPie/supplementary/ES-config
gdb ./es-config
run --settings ./settings.xml```

Still not affecting the gngeo controls, however.