6eb5566104
Possibly broken by acd1b0b7f9.
Though returning a collection property from an RNA function doesn't
seem to have been used before. The mistakes are relatively obvious.
The RNA parameter list data isn't initialized so placement new and
calling the CollectionVector destructor manually are necessary.
This fix is necessary for #135734 which is targeted at 4.4.
Pull Request: https://projects.blender.org/blender/blender/pulls/135746