By Pat Forde The scion of the U.S.’s QB dynasty made his decision without any fanfare, and without the influence of family ties. Arch Manning did this his way. The family ties to Mississippi and Tennessee did not influence his college decision. Growing up in Louisiana did not bind him to LSU. The twin Southeastern Conference towers of Georgia and Alabama could not lure him. In the end, the latest member of the United States’s greatest quarterbacking family is blazing a different trail to Texas. His commitment to the Longhorns—announced out of the blue, in what appears to be his first and only …