Retiming versioning used incorrect source for strip length, so produced
inverted strips. Also it tried to scale sound strips by `speed_factor`,
but sound strips did not change length when retimed.
Finally, the original versioning code was in versioning_300.cc file,
even though it was released with 4.0 version.
Pull Request: https://projects.blender.org/blender/blender/pulls/123144