sockets: remove use of QemuOpts from header file

sockets: remove use of QemuOpts from header file

There are no callers of the sockets methods which accept
QemuOpts any more. Make all the QemuOpts related functions
static to avoid new callers being added, in preparation
for removal of all QemuOpts usage, in favour of QAPI
SocketAddress.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1452518225-11751-2-git-send-email-berrange@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>