Add the iptables wait flag change to more places

There were a few places that the last PR https://github.com/kubernetes/kubernetes/pull/54763 missed because the flags that PR covered were of the form -w2.  Some of the code had --wait=2.  This changes that code to use the same global variable for the wait setting so that everything is consistent.

pkg/util/iptables/iptables.go

@@ -592,7 +592,7 @@ func getIPTablesRestoreWaitFlag(exec utilexec.Interface, protocol Protocol) []st
 		return nil
 	}
 
-	return []string{"--wait=2"}
+	return []string{WaitSecondsString}
 }
 
 // getIPTablesRestoreVersionString runs "iptables-restore --version" to get the version string