bug#24547: 24.4; dired should colour in sockets and pipes

[Trent W. Buck]

With GNU ls --color in a terminal, different colors are used for

    regular files,
    directories,
    symlinks,
    sockets,
    pipes,
    (other stuff - dircolors?)

In dired, the first three get different faces,
but sockets and pipes look like regular files.

I think it's probably easy to fix sockets and pipes,
because the first character is "s" or "p",
at least in GNU ls output.