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/NatController.h b/NatController.h
index 1d328e5..c1979bb 100644
--- a/NatController.h
+++ b/NatController.h
@@ -31,6 +31,9 @@
     int disableNat(const int argc, char **argv);
     int setupIptablesHooks();
 
+    static const char* LOCAL_FORWARD;
+    static const char* LOCAL_NAT_POSTROUTING;
+
 private:
     int natCount;
     SecondaryTableController *secondaryTableCtrl;