PeerMan: rename drop_gossip method and fix bug

It's more accurate to name it as dropping gossip broadcasts, as it won't drop all gossip.
Also fix accidental flipped bool introduced in lightningdevkit#1660

lightning/src/ln/peer_handler.rs

@@ -398,12 +398,9 @@ impl Peer {
 	}
 
 	/// Returns whether this peer's buffer is full and we should drop gossip messages.
-	fn buffer_full_drop_gossip(&self) -> bool {
-		if self.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP
-			|| self.msgs_sent_since_pong > BUFFER_DRAIN_MSGS_PER_TICK * FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO {
-				return false
-		}
-		true
+	fn buffer_full_drop_gossip_broadcast(&self) -> bool {
+		self.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP ||
+			self.msgs_sent_since_pong > BUFFER_DRAIN_MSGS_PER_TICK * FORWARD_INIT_SYNC_BUFFER_LIMIT_RATIO
 	}
 }
 
@@ -1325,7 +1322,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
 							!peer.should_forward_channel_announcement(msg.contents.short_channel_id) {
 						continue
 					}
-					if peer.buffer_full_drop_gossip() {
+					if peer.buffer_full_drop_gossip_broadcast() {
 						log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
 						continue;
 					}
@@ -1349,7 +1346,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
 							!peer.should_forward_node_announcement(msg.contents.node_id) {
 						continue
 					}
-					if peer.buffer_full_drop_gossip() {
+					if peer.buffer_full_drop_gossip_broadcast() {
 						log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
 						continue;
 					}
@@ -1372,7 +1369,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref, CMH: Deref> P
 							!peer.should_forward_channel_announcement(msg.contents.short_channel_id)  {
 						continue
 					}
-					if peer.buffer_full_drop_gossip() {
+					if peer.buffer_full_drop_gossip_broadcast() {
 						log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
 						continue;
 					}