handle dir

-- aaa/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git svn https://vcs-test.golang.org/svn/test1-svn-git">
-- git-README-only/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git/git-README-only git https://vcs-test.golang.org/git/README-only">
-- git-README-only/other/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git/git-README-only git https://vcs-test.golang.org/git/README-only">
-- git-README-only/pkg/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git/git-README-only git https://vcs-test.golang.org/git/README-only">
-- index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git svn https://vcs-test.golang.org/svn/test1-svn-git">
-- other/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git svn https://vcs-test.golang.org/svn/test1-svn-git">
-- tiny/index.html --
<!DOCTYPE html>
<html>
<meta name="go-import" content="vcs-test.golang.org/go/test1-svn-git svn https://vcs-test.golang.org/svn/test1-svn-git">
