[Graph]: Fixed overflow error in delta_mod & set_changed bug
[Graph]: Fixed overflow error in delta_mod & set_changed bug

flashxio/FlashX,icoming/FlashX,zheng-da/FlashX,icoming/FlashX,flashxio/FlashX,flashxio/FlashX,zheng-da/FlashX,icoming/FlashGraph,icoming/FlashGraph,icoming/FlashX,zheng-da/FlashX,icoming/FlashGraph,icoming/FlashX,zheng-da/FlashX,icoming/FlashGraph,flashxio/FlashX,icoming/FlashX,zheng-da/FlashX,flashxio/FlashX,icoming/FlashGraph,flashxio/FlashX