Fix missing capitalization

ArduPlane/Attitude.pde

@@ -317,7 +317,7 @@ static void set_servos(void)
 					(control_mode == CIRCLE || control_mode >= FLY_BY_WIRE_B) &&
 					(abs(home.alt - current_loc.alt) < 1000) &&
 					((g.airspeed_enabled ? airspeed : g_gps->ground_speed) < 500 ) &&
-					!(control_mode==Auto && takeoff_complete == false)
+					!(control_mode==AUTO && takeoff_complete == false)
 				) {
 				g.channel_throttle.servo_out = 0;
 				g.channel_throttle.calc_pwm();