In F.B.I., Innocent Detainee Found Unlikely Ally By NINA BERNSTEIN t took no more than a week for James P. Wynne, a veteran F.B.I. investigator, to confirm the harmless truth that only now, more than two years later, he is ready to talk about. The small foreign man he helped arrest for videotaping outside an office building in Queens on Oct. 25, 2001, was no terrorist. He was a Buddhist from Nepal planning to return there after five years of odd jobs at places like a Queens pizzeria and a Manhattan flower shop. He was taping New York street scenes...