[bug-OpenMage#650] Cart price gets deducted on page reload when qty > stock

Steps to reproduce:

1. Disable product backorders (if enabled)
2. Add Stock qty into a product
3. Add product to cart
4. Change product cart qty to something above the available qty
5. Along the error message "The requested quantity for "%s" is not available."
   the unit price gets deducted.
6. Reload the page and unit price is deducted again.

Introduced in 1.9.3.1

Author: henrykbrzoska

app/code/core/Mage/Sales/Model/Quote/Address/Total/Subtotal.php

@@ -111,7 +111,7 @@ protected function _initItem($address, $item)
             $item->setPrice($finalPrice)
                 ->setBaseOriginalPrice($finalPrice);
             $item->calcRowTotal();
-        } else if (!$quoteItem->getParentItem() && !$item->getHasError()) {
+        } else if (!$quoteItem->getParentItem()) {
             $finalPrice = $product->getFinalPrice($quoteItem->getQty());
             $item->setPrice($finalPrice)
                 ->setBaseOriginalPrice($finalPrice);