scritps: fix command existence checking and coding style
scritps: fix command existence checking and coding style

jinghaomiao/apollo,xiaoxq/apollo,ApolloAuto/apollo,xiaoxq/apollo,xiaoxq/apollo,ycool/apollo,wanglei828/apollo,ycool/apollo,wanglei828/apollo,jinghaomiao/apollo,xiaoxq/apollo,ApolloAuto/apollo,ycool/apollo,ApolloAuto/apollo,ApolloAuto/apollo,ApolloAuto/apollo,xiaoxq/apollo,jinghaomiao/apollo,ycool/apollo,wanglei828/apollo,ycool/apollo,jinghaomiao/apollo,ycool/apollo,ApolloAuto/apollo,wanglei828/apollo,jinghaomiao/apollo,xiaoxq/apollo,wanglei828/apollo,wanglei828/apollo,jinghaomiao/apollo