Workorders cleared with hireling removal.

src/engine/objects/NPC.java

@@ -651,8 +651,9 @@ public class NPC extends AbstractCharacter {
                 Logger.error(e.getMessage());
             }
 
-            if (minionMob.getParentZone() != null)
-                minionMob.getParentZone().zoneMobSet.remove(minionMob);
+            if (minionMob.parentZone != null) {
+                minionMob.parentZone.zoneMobSet.remove(minionMob);
+            }
 
             WorldGrid.RemoveWorldObject(minionMob);
             DbManager.removeFromCache(minionMob);