MEXICO CITY — Authorities in southern Mexico disarmed and placed under investigation the entire police force in the once-glittering resort of Acapulco on Tuesday, claiming the local cops were infiltrated by drug gangs.Officials in Guerrero state issued arrest warrants for two top Acapulco police commanders, accusing them of homicide. It was the latest fall from grace for Acapulco, which was a favorite haunt of movie stars in the 1960s but has since fallen victim to warring drug gangs.The state government said it took the step "because of suspicion that the force had probably . . .