mdadm: fix wrong condition for go to abort

When parse_cluster_confirm_arg return 0, it means the
arg are parsed successfully, so change !rv to rv.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: NeilBrown <neilb@suse.com>

Manage.c

@@ -1336,7 +1336,7 @@ int Manage_subdevs(char *devname, int fd,
 			rv = parse_cluster_confirm_arg(dv->devname,
 						       &dv->devname,
 						       &raid_slot);
-			if (!rv) {
+			if (rv) {
 				pr_err("Could not get the devname of cluster\n");
 				goto abort;
 			}