[PATCH] dix: check for NULL pointer before dereferences it in DeviceEnterLeaveEvent

[Dan Nicholson]

On Fri, Apr 16, 2010 at 8:42 AM, Tiago Vignatti
<tiago.vignatti at nokia.com> wrote:
> Both mouse and mouse->button are already used before their checking were being
> performed. So check on the beginning.
>
> Signed-off-by: Tiago Vignatti <tiago.vignatti at nokia.com>

Reviewed-by: Dan Nicholson <dbn.lists at gmail.com>