* Was target of conservative Tea Party movement * Rebelled against anti-tax lobbyist Grover Norquist By Rachelle Younglai WASHINGTON, Jan 25 (Reuters) - Republican U.S. Senator Saxby Chambliss of Georgia announced on Friday he will not seek a third term in 2014, saying he was fed up with the partisan gridlock in Congress that has left the country lurching from one fiscal crisis to another.