update .travis.yml
update .travis.yml

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