The issue was caused by a non-initialized ibuf_ used to set the non-color
space to. For now limit the tweaks to the image data-block, which is always
ensured. This makes it consistent with the GPU compositor which does not
have access to ibuf at the moment when the meta-data is being checked.
Ideally we do need to set the color space, but it needs to happen consistently,
and in a thread-safe manner. The way how the CPU compositor releases the
ibuf right after acquisition does not feel safe, so less we rely on it is
better.
f4a7c42255