Blender Git Loki

This is the famous proverbal example of someone trying to get a 4 legged
table stable... you keep correcting leg sizes until no table is left
anymore! :)

This commit restores the displacement direction from 2.37a code, which was
negated 5 months ago to fix a change in renderconverter.c, but somehow is
not needed anymore. The regression displacement file now renders OK again.