add coverity check
add coverity check

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