fix/workaround for v3d object mode selector flipping direction

Allow menu functions to define their own direction, this way
menu_item_enum_opname_menu can keep menu flipping from 2.69.

source/blender/editors/interface/interface_layout.c

@@ -1793,6 +1793,9 @@ static void menu_item_enum_opname_menu(bContext *UNUSED(C), uiLayout *layout, vo
 
 	uiLayoutSetOperatorContext(layout, lvl->opcontext);
 	uiItemsEnumO(layout, lvl->opname, lvl->propname);
+
+	/* override default, needed since this was assumed pre 2.70 */
+	uiBlockSetDirection(layout->root->block, UI_DOWN);
 }
 
 void uiItemMenuEnumO(uiLayout *layout, bContext *C, const char *opname, const char *propname, const char *name, int icon)