`rmdir --missing-okay` not working on ESP32 w. MicroPython

[dybber]

When issuing ampy rmdir directoryname/ --missing-okay, on a directory that doesn't exist, ampy still errors.

The problem seems to be this line, which checks for a very specific error string: https://github.com/scientifichackers/ampy/blob/master/ampy/files.py#L292

However, on the ESP32 version of MicroPython, that error string is just:

OSError: -2

[0x5e]

Same on me. --missing-okay not working.