Plane: Don't lock home altitude to AHRS origin

ArduPlane/commands.cpp

@@ -137,16 +137,9 @@ void Plane::update_home()
     }
     if (home_is_set == HOME_SET_NOT_LOCKED) {
         Location loc = gps.location();
-        Location origin;
-        // if an EKF origin is available then we leave home equal to
-        // the height of that origin. This ensures that our relative
-        // height calculations are using the same origin
-        if (ahrs.get_origin(origin)) {
-            loc.alt = origin.alt;
-        }
         ahrs.set_home(loc);
         Log_Write_Home_And_Origin();
-        GCS_MAVLINK::send_home_all(gps.location());
+        GCS_MAVLINK::send_home_all(loc);
     }
     barometer.update_calibration();
 }