mi: UpdateSprite only if the device is attached.

[John Tapsell]

Hi all,

  This commit introduces a bug for me.
  I use Xorg with no mouse attached, but use synergy to control the
mouse.  The commit means that I no longer have a visible mouse cursor.
 The mouse cursor is still 'there' in terms that I can click buttons
etc with it, but it's just not visible.

commit 9ce995373e4aa4b1bf51b4adafa2324f781ec1cd
Author: Peter Hutterer <peter.hutterer at redhat.com>
Date:   Mon Dec 1 21:32:39 2008 +1000

    mi: UpdateSprite only if the device is attached.


John