ClusterData: Remove all_nodes variable in new()

This variable was unused, probably some leftover. It's interesting that
we didn't get any warnings about it not being used (no reads, it was
only written).

scylla/src/transport/cluster.rs

@@ -292,7 +292,6 @@ impl ClusterData {
             HashMap::with_capacity(metadata.peers.len());
         let mut ring: Vec<(Token, Arc<Node>)> = Vec::new();
         let mut datacenters: HashMap<String, Datacenter> = HashMap::new();
-        let mut all_nodes: Vec<Arc<Node>> = Vec::with_capacity(metadata.peers.len());
 
         for peer in metadata.peers {
             // Take existing Arc<Node> if possible, otherwise create new one
@@ -344,8 +343,6 @@ impl ClusterData {
             for token in peer_tokens {
                 ring.push((token, node.clone()));
             }
-
-            all_nodes.push(node);
         }
 
         Self::update_rack_count(&mut datacenters);