Cleanup: move console scrollback initialization into versioning

source/blender/blenloader/intern/versioning_userdef.c

@@ -674,6 +674,9 @@ void BLO_version_defaults_userpref_blend(Main *bmain, UserDef *userdef)
       userdef->view_rotate_sensitivity_turntable = DEG2RADF(0.4f);
       userdef->view_rotate_sensitivity_trackball = 1.0f;
     }
+    if (userdef->scrollback == 0) {
+      userdef->scrollback = U_default.scrollback;
+    }
     /* pass */
   }