Fix treasury kept and spend when emptied (#3880)

* Now construct_runtime must include treasury config so account is created at genesis.
* if it doesn't though it is ok, account will be created when the amount put is more than existential deposit.

substrate/node/cli/src/chain_spec.rs

@@ -273,6 +273,7 @@ pub fn testnet_genesis(
 			authorities: vec![],
 		}),
 		membership_Instance1: Some(Default::default()),
+		treasury: Some(Default::default()),
 	}
 }