Fix counter leak
Fix counter leak

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