In the Arab world, leaders greet each other with exaggerated gestures of affection all the time - and it means nothing. A leader will bow to another, a leader will kiss the forehead of another, etc. The late president Arafat was the best of them, he once kissed the Sultan of Oman nine times - pretty much everywhere on his face.
But it means nothing. If anything, I think Obama's bow (if it was a bow) shows a shrewd operator who knows how to win people over. Obama has out-Arab'ed the Arabs.