Fix (unreported) non-official X3D add-on enabled in factory startup.

Forgot to remove it from there when I moved it to community-supported
status last week.

Also raising subversion.

source/blender/blenkernel/BKE_blender_version.h

@@ -27,7 +27,7 @@
  * \note Use #STRINGIFY() rather than defining with quotes.
  */
 #define BLENDER_VERSION 281
-#define BLENDER_SUBVERSION 8
+#define BLENDER_SUBVERSION 9
 /** Several breakages with 280, e.g. collections vs layers. */
 #define BLENDER_MINVERSION 280
 #define BLENDER_MINSUBVERSION 0

source/blender/blenloader/intern/versioning_280.c

@@ -3766,8 +3766,7 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
     }
   }
 
-  {
-    /* Versioning code until next subversion bump goes here. */
+  if (!MAIN_VERSION_ATLEAST(bmain, 281, 9)) {
     for (bScreen *screen = bmain->screens.first; screen; screen = screen->id.next) {
       for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
         for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
@@ -3842,4 +3841,8 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
       }
     }
   }
+
+  {
+    /* Versioning code until next subversion bump goes here. */
+  }
 }

source/blender/blenloader/intern/versioning_userdef.c

@@ -610,6 +610,11 @@ void BLO_version_defaults_userpref_blend(Main *bmain, UserDef *userdef)
     userdef->drag_threshold_tablet = 10;
   }
 
+  if (!USER_VERSION_ATLEAST(281, 9)) {
+    /* X3D is no longer enabled by default. */
+    BKE_addon_remove_safe(&userdef->addons, "io_scene_x3d");
+  }
+
   /**
    * Include next version bump.
    */