qcow2_update_cluster_refcount() does not have any quick access to the
new refcount value, it has to call qcow2_get_refcount(). Some callers do
not need that new value at all, others call qcow2_get_refcount()
themselves anyway (albeit in a different code path, which can however be
easily changed), therefore there is no advantage in making
qcow2_update_cluster_refcount() return the new value. Drop it.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>