f drop unused mut in monitor_tests as well

Author: TheBlueMatt

lightning/src/ln/mod.rs

@@ -53,6 +53,7 @@ mod reorg_tests;
 #[allow(unused_mut)]
 mod onion_route_tests;
 #[cfg(test)]
+#[allow(unused_mut)]
 mod monitor_tests;
 
 pub use self::peer_channel_encryptor::LN_MAX_MSG_LEN;