Revert "Clean up FIP properly on external net deletion"

Reverting since this patch should not have been
backported to 2014.1.3.

Fixes: MNP-27
This reverts commit 9a6fbb0.

midonet/neutron/plugin.py

@@ -219,7 +219,6 @@ def delete_network(self, context, id):
         LOG.info(_("MidonetPluginV2.delete_network called: id=%r"), id)
 
         with context.session.begin(subtransactions=True):
-            self._process_l3_delete(context, id)
             super(MidonetPluginV2, self).delete_network(context, id)
             self.api_cli.delete_network(id)