Update logging.cc
Update logging.cc

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