global: use static method to construct AP_Terrain

ArduCopter/Copter.cpp

@@ -66,9 +66,6 @@ Copter::Copter(void)
     mainLoop_count(0),
     rtl_loiter_start_time(0),
     auto_trim_counter(0),
-#if AP_TERRAIN_AVAILABLE && AC_TERRAIN
-    terrain(ahrs, mission, rally),
-#endif
 #if PRECISION_LANDING == ENABLED
     precland(ahrs, inertial_nav),
 #endif

ArduCopter/Copter.h

@@ -584,7 +584,7 @@ private:
 
     // terrain handling
 #if AP_TERRAIN_AVAILABLE && AC_TERRAIN
-    AP_Terrain terrain;
+    AP_Terrain terrain = AP_Terrain::create(ahrs, mission, rally);
 #endif
 
     // Precision Landing

ArduPlane/Plane.h

@@ -611,7 +611,7 @@ private:
 
     // terrain handling
 #if AP_TERRAIN_AVAILABLE
-    AP_Terrain terrain {ahrs, mission, rally};
+    AP_Terrain terrain = AP_Terrain::create(ahrs, mission, rally);
 #endif
 
     AP_Landing landing {mission,ahrs,SpdHgt_Controller,nav_controller,aparm,

ArduSub/Sub.cpp

@@ -56,9 +56,6 @@ Sub::Sub(void)
           pmTest1(0),
           fast_loopTimer(0),
           mainLoop_count(0),
-#if AP_TERRAIN_AVAILABLE && AC_TERRAIN
-          terrain(ahrs, mission, rally),
-#endif
           in_mavlink_delay(false),
           param_loader(var_info),
           last_pilot_yaw_input_ms(0)

ArduSub/Sub.h

@@ -436,7 +436,7 @@ private:
 
     // terrain handling
 #if AP_TERRAIN_AVAILABLE && AC_TERRAIN
-    AP_Terrain terrain;
+    AP_Terrain terrain = AP_Terrain::create(ahrs, mission, rally);
 #endif
 
     // use this to prevent recursion during sensor init