unbreak usb pass-through on linux.

Changes:
  * Re-add the 'dev->fd = fd;' line which the qdev patches dropped
    by mistake.
  * call qdev_init() so the newly created usb device is plugged into
    a usb port and thus actually visible to the guest.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/usb-linux.c b/usb-linux.c
index c434e4f..2b7b092 100644
--- a/usb-linux.c
+++ b/usb-linux.c
@@ -922,6 +922,7 @@
 
     dev->bus_num = bus_num;
     dev->addr = addr;
+    dev->fd = fd;
 
     /* read the device description */
     dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));
@@ -979,6 +980,7 @@
 
     hostdev_link(dev);
 
+    qdev_init(&d->qdev);
     return (USBDevice *) dev;
 
 fail: