[Graph]: fix a bug in traversing on both types of edges in BFS
[Graph]: fix a bug in traversing on both types of edges in BFS

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