patch applied (nhc98): Prelude sum and product should really use foldl' not foldl.

Thu Mar  1 08:54:37 PST 2007  Malcolm.Wallace@xxxxxxxxxxxxx
  UNDO: Prelude sum and product should really use foldl' not foldl.

    M ./src/prelude/PreludeList/Foldl.hs -4
    M ./src/prelude/PreludeList/Product.hs -3 +1
    M ./src/prelude/PreludeList/Sum.hs -3 +1