network: fix bug in BIP37 relay flag handling.

The relay flag in the version message is used in conjunction with BIP37 to
receive bloom-filtered transactions.  When it is set to false, transactions are
not relayed until a bloom filter is set.  Since we don't implement BIP37 (it's
not useful for shielded transactions), this means we'll never receive
transactions.

zebra-network/src/peer_set/initialize.rs

@@ -65,6 +65,7 @@ where
             // XXX .with_addr(addr) once we can access our configured address
             .with_advertised_services(PeerServices::NODE_NETWORK)
             .with_user_agent(crate::constants::USER_AGENT.to_string())
+            .want_transactions(true)
             .finish()
             .expect("configured all required parameters");
         (