Update client on cancelled entity naming. Fixes BUKKIT-4396

src/main/java/net/minecraft/server/PlayerConnection.java

@@ -1110,6 +1110,10 @@ public class PlayerConnection extends Connection {
                             // Refresh the current leash state
                             this.sendPacket(new Packet39AttachEntity(1, entity, ((EntityInsentient) entity).bE()));
                         }
+                        if (itemInHand != null && itemInHand.id == Item.NAME_TAG.id && entity instanceof EntityInsentient) {
+                            // Refresh the current entity metadata
+                            this.sendPacket(new Packet40EntityMetadata(entity.id, entity.datawatcher, true));
+                        }
                         return;
                     }
                     // CraftBukkit end