UNDER SUSPICION -- Stuart Damon (left) is at the mercy of Guy Rolfe and his gunman in the new color adventure series “The Champions” which replaces “Rowan and Martin’s Laugh-In” for the Summer on the NBC Television Network, Monday, June 10 (8-9 p.m. NYT). Premiere episode is “To Trap a Rat.”   (5/17/68) (D)      NBC-TV CAPTION SUBJECTS:     (foreground) Stuart Damon (left) and Guy Rolfe PROGRAM:     “The Champions” premiere episode “To Trap a Rat” TIME:     NBC Television Network colorcast, Monday, June 10 (8-9 p.m. NYT)