It's admittedly a pretty hairy question, but one that has dogged moviegoers since 1959: What color was "The Shaggy Dog," as in the Walt Disney movie of the same name? Thanks to the "miracle" of colorization, Disney itself has provided the answer: the Bratislavan sheep dog is white with brown spots. When it appears on ABC Sunday night, "The Shaggy Dog" will become the first colorized movie to be shown on a major network. The film, to be shown in two parts concluding on Oct. 25, will be followed by its sequel, "The Shaggy D.A."--which was filmed in color.