socket: pass correct size in net_socket_send()

We should pass the size of packet instead of the remaining to
qemu_send_packet_async().

Fixes: 6e99c63
       ("net/socket: Drop net_socket_can_send")

Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1436259656-24263-1-git-send-email-jasowang@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

net/socket.c

@@ -213,7 +213,7 @@ static void net_socket_send(void *opaque)
             if (s->index >= s->packet_len) {
                 s->index = 0;
                 s->state = 0;
-                if (qemu_send_packet_async(&s->nc, s->buf, size,
+                if (qemu_send_packet_async(&s->nc, s->buf, s->packet_len,
                                            net_socket_send_completed) == 0) {
                     net_socket_read_poll(s, false);
                     break;