Core: fixed warning introduced in last commit

(cherry picked from commit fe0c07a6fe4dea8772e69ec8ad491bdda7f61746)

src/server/scripts/EasternKingdoms/SunwellPlateau/boss_kalecgos.cpp

@@ -565,6 +565,8 @@ public:
             player->GetSession()->SendNotification(GO_FAILED);
             return true;
         }
+#else
+        (void)go;
 #endif
 
         player->CastSpell(player, SPELL_TELEPORT_SPECTRAL, true);