bug#19394: 25.0.50; mpc does not handle MPD_HOST=socket

[Eli Zaretskii]

> From: Mark Oteiza <mvoteiza@udel.edu>
> Date: Sun, 02 Aug 2015 14:36:37 -0400
> 
> Here's a patch for handling the MPD_HOST being a socket.

Thanks.

> +                                             :remote (if (string-prefix-p 
> "/" host)
> +                                                         host))

This looks wrong to me, the proper test for a remote file name is
file-remote-p (if this is what you want to test here).