Creature/Script: npc_tallhorn_stag

Ref #2623

(cherry picked from commit bfffa5d45e)

src/server/scripts/Northrend/zone_grizzly_hills.cpp

@@ -373,6 +373,8 @@ public:
                 }
                 _phase = 0;
             }
+            if (!UpdateVictim())
+                return;
             DoMeleeAttackIfReady();
         }
         private: