OMAHA, Neb. (AP) – Officials say the woman whose body was found floating in a private lake in central Omaha had drowned accidentally.     Douglas County Attorney Don Kleine, in his capacity as county coroner, said Thursday that the body of 62-year-old Mary LaPuzza showed no trauma. He said lab tests showed no signs of drugs oralcohol.     The body was found early May 2 near the shore of Regency Lake. It was clad in running clothes.