Remove useless code
Remove useless code

baidu/bfs,imotai/bfs,yvxiang/coverage_for_bfs,00k/ToyDFS,bluebore/dfs,myawan/bfs-1,bluebore/bfs,bluebore/bfs,bluebore/dfs,lylei/dfs,bluebore/dfs,yvxiang/dfs,yvxiang/dfs,lylei/dfs,yvxiang/dfs,yvxiang/coverage_for_bfs,linyvxiang/dfs,yvxiang/dfs,myawan/bfs-1,00k/ToyDFS,lylei/dfs,imotai/bfs,bluebore/bfs,linyvxiang/dfs,imotai/bfs,myawan/bfs-1,baidu/bfs,yvxiang/coverage_for_bfs,baidu/bfs,yvxiang/coverage_for_bfs,baidu/bfs,linyvxiang/dfs,myawan/bfs-1,lylei/dfs