[Matrix]: fix a compilation error in sort.h
[Matrix]: fix a compilation error in sort.h

icoming/FlashGraph,flashxio/FlashX,flashxio/FlashX,icoming/FlashX,flashxio/FlashX,icoming/FlashX,icoming/FlashGraph,flashxio/FlashX,icoming/FlashX,flashxio/FlashX,icoming/FlashGraph,icoming/FlashGraph,flashxio/FlashX,icoming/FlashX,icoming/FlashX,icoming/FlashGraph