Add assertion since we now have a pub field that is PartialEq

We previously were only able to assert that the route graph
serialization roundtrips were good by comparing the network
messages returned from them, but we can now do better as the graph
is exposed publicly via a simple datastructure that implements
PartialEq.

Author: TheBlueMatt

lightning/src/ln/functional_test_utils.rs

@@ -102,6 +102,7 @@ impl<'a, 'b, 'c> Drop for Node<'a, 'b, 'c> {
 				let network_graph_ser = self.net_graph_msg_handler.network_graph.read().unwrap();
 				network_graph_ser.write(&mut w).unwrap();
 				let network_graph_deser = <NetworkGraph>::read(&mut ::std::io::Cursor::new(&w.0)).unwrap();
+				assert!(network_graph_deser == *self.net_graph_msg_handler.network_graph.read().unwrap());
 				let net_graph_msg_handler = NetGraphMsgHandler::from_net_graph(
 				   Arc::clone(&self.chain_monitor) as Arc<chaininterface::ChainWatchInterface>,
 				   Arc::clone(&self.logger) as Arc<Logger>, RwLock::new(network_graph_deser)