I'd imagine that it's called redo because at some point, probably very late in the model development stage, someone decided that the erinyes needed a new texture job. But it wouldn't be ready in time to compile the model, so the texture was labled redo so that it was automatically flagged to be gone back over by the art staff. As sloppy as redo.pcx in sparky is, it wouldn't suprise me if they never got around to it.
The Erinyes is also slightly disturbing because that one texture (including the low-res equivalents) is listed no less than twenty-one times in the model file. I'll bet that despite only having one texture, that ship makes HTL scream bloody murder every time it gets processed.