make sure listParts returns parts that are valid (#20390)

docs/bucket/replication/setup_2site_existing_replication.sh

@@ -24,6 +24,9 @@ catch() {
 	rm -rf /tmp/multisitea
 	rm -rf /tmp/multisiteb
 	rm -rf /tmp/data
+	if [ $# -ne 0 ]; then
+		exit $#
+	fi
 }
 
 catch