Consolidate iptables chain management.

Move creation and management of module iptables chains up into
CommandListener, which gives better visibility into ordering.

Change-Id: If0c94187c6e59a20840b035d7241057f45a0f74b
diff --git a/IdletimerController.h b/IdletimerController.h
index 6167b48..2af0d9b 100644
--- a/IdletimerController.h
+++ b/IdletimerController.h
@@ -30,6 +30,9 @@
                                  const char *classLabel);
     bool setupIptablesHooks();
 
+    static const char* LOCAL_NAT_PREROUTING;
+    static const char* LOCAL_NAT_POSTROUTING;
+
  private:
     enum IptOp { IptOpAdd, IptOpDelete };
     int setDefaults();