Mismatch in generated image size with Save Screenshot

On occasion, ParaView fails to generate an output image matching the requested size. Simply run the script as follows:

# Using ParaView 5.4.1 on Linux
> pvpython -dr foo.py

Instead of generating a 300x300 image, it generates a 300x299 image.

The issue arises because the vertical layout size in the file is odd and then when it splits that into two parts, the math in vtkSMViewLayoutProxy::SetSize has rounding issues and looses 1 pixel from the requested size.