And if he had jumped off of both feet and landed on both feet, that would have been a travel. Go back and watch it. He dribbles, puts down one foot and jumps backwards to land on both feet. I'll post (again) what the NBA says about it:
If a player jumps off one foot on the count of one he may land with both feet simultaneously for count two. In this situation, the player may not pivot with either foot and if one or both feet leave the floor the ball must be released before either return to the floor.