md-cluster: clean related infos of cluster

cluster_info and bitmap_info.nodes also need to be
cleared when array is stopped.

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
1 file changed