* If required roles are not found, refuse to load the config
* Use "default" role as fallback for all roles, following the
OpenColorIO docs.
* Use bundled config if loading environment config fails,
instead using very limited fallback config.
* Fix OCIO_exit get called on failed config load, causing
crash when trying to load the next config.
Pull Request: https://projects.blender.org/blender/blender/pulls/119435
e9ca817d5f