util: rename qemu_*block() socket functions

The qemu_*block() functions are meant to be be used with sockets (the
win32 implementation expects SOCKET)

Over time, those functions where used with Win32 SOCKET or
file-descriptors interchangeably. But for portability, they must only be
used with socket-like file-descriptors. FDs can use
g_unix_set_fd_nonblocking() instead.

Rename the functions with "socket" in the name to prevent bad usages.

This is effectively reverting commit f9e8cacc5557e43 ("oslib-posix:
rename socket_set_nonblock() to qemu_set_nonblock()").

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index f66fbba..232984a 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -65,7 +65,7 @@
 {
     int i;
     for (i = 0; i < vmsg->fd_num; i++) {
-        qemu_set_nonblock(vmsg->fds[i]);
+        qemu_socket_set_nonblock(vmsg->fds[i]);
     }
 }
 
@@ -270,7 +270,7 @@
 
         vu_fd_watch->fd = fd;
         vu_fd_watch->cb = cb;
-        qemu_set_nonblock(fd);
+        qemu_socket_set_nonblock(fd);
         aio_set_fd_handler(server->ioc->ctx, fd, true, kick_handler,
                            NULL, NULL, NULL, vu_fd_watch);
         vu_fd_watch->vu_dev = vu_dev;