f catch underflow too

Author: TheBlueMatt

lightning/src/routing/network_graph.rs

@@ -1090,7 +1090,8 @@ impl NetworkGraph {
 	pub fn remove_stale_channels_with_time(&self, current_time_unix: u64) {
 		let mut channels = self.channels.write().unwrap();
 		// Time out if we haven't received an update in at least 14 days.
-		if current_time_unix > u32::max_value() { return; } // Remove by 2106
+		if current_time_unix > u32::max_value() as u64 { return; } // Remove by 2106
+		if current_time_unix < STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS { return; }
 		let min_time_unix: u32 = (current_time_unix - STALE_CHANNEL_UPDATE_AGE_LIMIT_SECS) as u32;
 		// Sadly BTreeMap::retain was only stabilized in 1.53 so we can't switch to it for some
 		// time.