Fallback handler could not load library libadvapi32.dll

I am running ai2thor on a remote machine (AWS ec2 instance running Ubuntu 18.04). I'm using version 2.7.2. When I try to run the following program
```python
from pprint import pprint
import ai2thor.controller
import cv2

if __name__ == '__main__':
controller = ai2thor.controller.Controller(scene='FloorPlan28')
event = controller.step(action='RotateRight')
pprint(event.metadata['agent'])
cv2.imwrite("output.png", event.cv2img)
```
I got a bunch of messages saying
```
Fallback handler could not load library /.../.ai2thor/thor-Linux64-a6674babc132c5d63d18c82a0e14c01d236aa981/thor-Linux64-a6674babc132c5d63d18c82a0e14c01d236aa981_Data/Mono/libadvapi32.dll
```
It is indeed the case that `Mono` does not exist under the `thor-Linux64-a667..._Data` folder. There is only `MonoBleedingEdge`. This is an issue.

This message didn't appear to affect the program; it still saved an image. I wonder if that will affect the rendering of the image.