qvirtqueue_setup() allocates the vring and virtqueue state. So far
there has been no function to free it. Callers have been using
guest_free() for the vring but forgot to free the QVirtQueue state.
This patch solves the memory leak by introducing qvirtqueue_cleanup().
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
f1d3b99154