SAN FRANCISCO (Reuters) - China's Lenovo Group Ltd. (0992) won clearance from a U.S. national security oversight committee to acquire IBM's (IBM) personal computer business, the companies said on Wednesday, overcoming resistance from some U.S. lawmakers An IBM executive said the high-level U.S. committee had given the deal its unanimous consent -- the final external approval needed -- putting the $1.25 billion PC sale on track to close in the second quarter as originally planned. "We were able to get unanimous agreement from the members of the committee," Stephen Ward, the general manager of IBM's Personal Systems Division, said in...