Fix return code on failure (#662)
Fix return code on failure (#662)

(#661) return 1 when nameserver starts failed
yvxiang/dfs,lylei/dfs,bluebore/bfs,lylei/dfs,yvxiang/coverage_for_bfs,bluebore/bfs,baidu/bfs,yvxiang/coverage_for_bfs,linyvxiang/dfs,yvxiang/coverage_for_bfs,bluebore/dfs,bluebore/dfs,yvxiang/dfs,yvxiang/coverage_for_bfs,bluebore/bfs,baidu/bfs,bluebore/dfs,baidu/bfs,linyvxiang/dfs,lylei/dfs,baidu/bfs,linyvxiang/dfs,yvxiang/dfs,lylei/dfs,yvxiang/dfs