dump: Don't loose dump_namespaces error

In case if dump_namespaces failed we may have
ret shadowed and erroneously report checkpoint
success.
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-dump.c

@@ -1842,9 +1842,11 @@ int cr_dump_tasks(pid_t pid)
 	if (ret)
 		goto err;
 
-	if (root_ns_mask)
-		if (dump_namespaces(root_item, root_ns_mask) < 0)
+	if (root_ns_mask) {
+		ret = dump_namespaces(root_item, root_ns_mask);
+		if (ret)
 			goto err;
+	}
 
 	ret = dump_cgroups();
 	if (ret)