Clean up TestKeysInterface random bytes override interface

Its very confusing to have multiple fields that do the same thing,
one of which isn't even used for its stated purpose anymore after
the previous few commits.

Author: TheBlueMatt

lightning/src/ln/functional_tests.rs

@@ -6001,7 +6001,7 @@ fn bolt2_open_channel_sending_node_checks_part1() { //This test needs to be on i
 	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 	//Force duplicate channel ids
 	for node in nodes.iter() {
-		*node.keys_manager.override_channel_id_priv.lock().unwrap() = Some([0; 32]);
+		*node.keys_manager.override_random_bytes.lock().unwrap() = Some([0; 32]);
 	}
 
 	// BOLT #2 spec: Sending node must ensure temporary_channel_id is unique from any other channel ID with the same peer.

lightning/src/ln/onion_route_tests.rs

@@ -317,7 +317,7 @@ fn test_onion_failure() {
 	let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[Some(config), Some(config), Some(node_2_cfg)]);
 	let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
 	for node in nodes.iter() {
-		*node.keys_manager.override_session_priv.lock().unwrap() = Some([3; 32]);
+		*node.keys_manager.override_random_bytes.lock().unwrap() = Some([3; 32]);
 	}
 	let channels = [create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known()), create_announced_chan_between_nodes(&nodes, 1, 2, InitFeatures::known(), InitFeatures::known())];
 	let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], 40000);

lightning/src/util/test_utils.rs

@@ -471,8 +471,7 @@ impl Logger for TestLogger {
 
 pub struct TestKeysInterface {
 	pub backing: keysinterface::PhantomKeysManager,
-	pub override_session_priv: Mutex<Option<[u8; 32]>>,
-	pub override_channel_id_priv: Mutex<Option<[u8; 32]>>,
+	pub override_random_bytes: Mutex<Option<[u8; 32]>>,
 	pub disable_revocation_policy_check: bool,
 	enforcement_states: Mutex<HashMap<[u8;32], Arc<Mutex<EnforcementState>>>>,
 	expectations: Mutex<Option<VecDeque<OnGetShutdownScriptpubkey>>>,
@@ -506,16 +505,9 @@ impl keysinterface::KeysInterface for TestKeysInterface {
 	}
 
 	fn get_secure_random_bytes(&self) -> [u8; 32] {
-		let override_channel_id = self.override_channel_id_priv.lock().unwrap();
-		let override_session_key = self.override_session_priv.lock().unwrap();
-		if override_channel_id.is_some() && override_session_key.is_some() {
-			panic!("We don't know which override key to use!");
-		}
-		if let Some(key) = &*override_channel_id {
-			return *key;
-		}
-		if let Some(key) = &*override_session_key {
-			return *key;
+		let override_random_bytes = self.override_random_bytes.lock().unwrap();
+		if let Some(bytes) = &*override_random_bytes {
+			return *bytes;
 		}
 		self.backing.get_secure_random_bytes()
 	}
@@ -543,8 +535,7 @@ impl TestKeysInterface {
 		let now = Duration::from_secs(genesis_block(network).header.time as u64);
 		Self {
 			backing: keysinterface::PhantomKeysManager::new(seed, now.as_secs(), now.subsec_nanos(), seed),
-			override_session_priv: Mutex::new(None),
-			override_channel_id_priv: Mutex::new(None),
+			override_random_bytes: Mutex::new(None),
 			disable_revocation_policy_check: false,
 			enforcement_states: Mutex::new(HashMap::new()),
 			expectations: Mutex::new(None),