apply fix to the AbstractEntity

Author: Raphael Petrini

app/code/Magento/Eav/Model/Entity/AbstractEntity.php

@@ -1064,7 +1064,11 @@ protected function _loadModelAttributes($object)
         $selectGroups = $this->_resourceHelper->getLoadAttributesSelectGroups($selects);
         foreach ($selectGroups as $selects) {
             if (!empty($selects)) {
-                $select = $this->_prepareLoadSelect($selects);
+                if (is_array($selects)) {
+                    $select = $this->_prepareLoadSelect($selects);
+                } else {
+                    $select = $selects;
+                }
                 $values = $this->getConnection()->fetchAll($select);
                 foreach ($values as $valueRow) {
                     $this->_setAttributeValue($object, $valueRow);