Instead of zeroing out a C++ wrapper for a DNA struct, zero out just the
DNA struct itself.
The C++ wrapper adds no extra fields, and also no virtual functions, so
the old code was already safe. Now it's also semantically correct :)
No functional changes.
Reviewed by Omar, by locally applying my diff.
Pull Request: https://projects.blender.org/blender/blender/pulls/143184
edc4136c79