Fix p2p filter unconnected peers

neo/Network/P2P/LocalNode.cs

@@ -20,6 +20,7 @@ internal class RelayDirectly { public IInventory Inventory; }
         internal class SendDirectly { public IInventory Inventory; }
 
         public const uint ProtocolVersion = 0;
+        private const int MaxCountFromSeedList = 5;
 
         private static readonly object lockObj = new object();
         private readonly NeoSystem system;
@@ -123,7 +124,7 @@ public IEnumerable<IPEndPoint> GetUnconnectedPeers()
 
         protected override void NeedMorePeers(int count)
         {
-            count = Math.Max(count, 5);
+            count = Math.Max(count, MaxCountFromSeedList);
             if (ConnectedPeers.Count > 0)
             {
                 BroadcastMessage(MessageCommand.GetAddr);

neo/Network/P2P/Peer.cs

@@ -66,7 +66,7 @@ protected void AddPeers(IEnumerable<IPEndPoint> peers)
         {
             if (UnconnectedPeers.Count < UnconnectedMax)
             {
-                peers = peers.Where(p => p.Port != ListenerTcpPort || !localAddresses.Contains(p.Address));
+                peers = peers.Where(p => (p.Port != ListenerTcpPort || !localAddresses.Contains(p.Address)) && !ConnectedPeers.Values.Contains(p));
                 ImmutableInterlocked.Update(ref UnconnectedPeers, p => p.Union(peers));
             }
         }