Copter: update get_non_takeoff_throttle for 0 to 1 range

ArduCopter/Attitude.cpp

@@ -203,7 +203,7 @@ float Copter::get_pilot_desired_climb_rate(float throttle_control)
 // get_non_takeoff_throttle - a throttle somewhere between min and mid throttle which should not lead to a takeoff
 float Copter::get_non_takeoff_throttle()
 {
-    return (g.throttle_mid / 2.0f);
+    return (((float)g.throttle_mid/1000.0f)/2.0f);
 }
 
 float Copter::get_takeoff_trigger_throttle()