A man who attacked another motorist with a machete this afternoon in Scotts Valley, was arrested after being tazed by nearby C-H-P officers.   The confrontation in the road-rage incident happened in the parking lot at Victor Square.   Highway patrol officers who were having lunch at the shopping center responded, and tazed the man after he had slashed the other driver in the leg with the machete.   The victim was bleeding, however the wounds are described as minor.