[SAFS]: fix a bug in print_io_thread_stat().
[SAFS]: fix a bug in print_io_thread_stat().

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