SPIGOT-4310: Reset villager career level with trades

nms-patches/EntityVillager.patch

@@ -15,6 +15,15 @@
  
  public class EntityVillager extends EntityAgeable implements NPC, IMerchant {
  
+@@ -26,7 +34,7 @@
+     public int riches;
+     private String bO;
+     public int careerId;
+-    private int bQ;
++    public int bQ; // PAIL private->public
+     private boolean bR;
+     private boolean bS;
+     public final InventorySubcontainer inventory;
 @@ -38,7 +46,7 @@
  
      public EntityVillager(World world, int i) {

src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java

@@ -70,6 +70,7 @@ public class CraftVillager extends CraftAgeable implements Villager, InventoryHo
 
         if (resetTrades) {
             getHandle().trades = null;
+            getHandle().bQ = 0; // SPIGOT-4310
             getHandle().populateTrades();
         }
     }