By Joseph Ax WASHINGTON (Reuters) – Republican Texas Governor Greg Abbott won his party’s nomination on Tuesday to seek a third term in office, setting up a November contest with Democratic former Congressman Beto O’Rourke, U.S. media reported. Abbott, who was endorsed by former President Donald Trump, easily turned back several right-wing challengers, heads into the Nov. 8 general election as a favorite over O’Rourke, the state’s most prominent Democrat, is seeking to become the first Democratic governor of Texas in nearly three decades. Meanwhile, state Attorney General Ken Paxton was headed…