ENGCOM-2303: [Backport 2.1] Issue 14351: Product import doesn't chang…

…e \`Enable Qty Increments\` field magento#14380

 - Merge Pull Request magento#14380 from simpleadm/magento2:backport/2.1-fix-product-import-enable-qty-inc
 - Merged commits:
   1. ead41d9
   2. 053fea2

app/code/Magento/CatalogImportExport/Model/Import/Product.php

@@ -8,6 +8,7 @@
 
 namespace Magento\CatalogImportExport\Model\Import;
 
+use Magento\CatalogInventory\Api\Data\StockItemInterface;
 use Magento\Framework\App\Filesystem\DirectoryList;
 use Magento\CatalogImportExport\Model\Import\Product\RowValidatorInterface as ValidatorInterface;
 use Magento\Framework\Model\ResourceModel\Db\TransactionManagerInterface;
@@ -2549,7 +2550,10 @@ private function _setStockUseConfigFieldsValues($rowData)
     {
         $useConfigFields = array();
         foreach ($rowData as $key => $value) {
-            $useConfigName = self::INVENTORY_USE_CONFIG_PREFIX . $key;
+            $useConfigName = $key === StockItemInterface::ENABLE_QTY_INCREMENTS
+                ? StockItemInterface::USE_CONFIG_ENABLE_QTY_INC
+                : self::INVENTORY_USE_CONFIG_PREFIX . $key;
+
             if (isset($this->defaultStockData[$key])
                 && isset($this->defaultStockData[$useConfigName])
                 && !empty($value)