global: use static method to construct AP_OpticalFlow

APMrover2/Rover.h

@@ -185,7 +185,7 @@ private:
             FUNCTOR_BIND_MEMBER(&Rover::exit_mission, void));
 
 #if AP_AHRS_NAVEKF_AVAILABLE
-    OpticalFlow optflow{ahrs};
+    OpticalFlow optflow = OpticalFlow::create(ahrs);
 #endif
 
     // RSSI

ArduCopter/Copter.h

@@ -233,7 +233,7 @@ private:
 
     // Optical flow sensor
 #if OPTFLOW == ENABLED
-    OpticalFlow optflow{ahrs};
+    OpticalFlow optflow = OpticalFlow::create(ahrs);
 #endif
 
     // gnd speed limit required to observe optical flow sensor limits

ArduPlane/Plane.h

@@ -279,7 +279,7 @@ private:
 
 #if OPTFLOW == ENABLED
     // Optical flow sensor
-    OpticalFlow optflow{ahrs};
+    OpticalFlow optflow = OpticalFlow::create(ahrs);
 #endif
 
     // Rally Ponints

ArduSub/Sub.h

@@ -200,7 +200,7 @@ private:
 
     // Optical flow sensor
 #if OPTFLOW == ENABLED
-    OpticalFlow optflow {ahrs};
+    OpticalFlow optflow = OpticalFlow::create(ahrs);
 #endif
 
     // gnd speed limit required to observe optical flow sensor limits

libraries/AP_OpticalFlow/examples/AP_OpticalFlow_test/AP_OpticalFlow_test.cpp

@@ -34,7 +34,7 @@ public:
 };
 
 static DummyVehicle vehicle;
-static OpticalFlow optflow(vehicle.ahrs);
+static OpticalFlow optflow = OpticalFlow::create(vehicle.ahrs);
 
 void setup()
 {