MAGETWO-32921: Adapt Payment\Gateway framework to client requirement

- turned off libxml errors for html form converter

Author: dkvashninbay

app/code/Magento/Payment/Block/Transparent/Form.php

@@ -169,10 +169,11 @@ public function getCgiUrl()
      */
     public function getMethodConfigData($fieldName)
     {
-        if ($this->getMethod() instanceof TransparentInterface) {
-            return $this->getMethod()->getConfigInterface()->getValue($fieldName);
+        $method = $this->getMethod();
+        if ($method instanceof TransparentInterface) {
+            return $method->getConfigInterface()->getValue($fieldName);
         }
-        return $this->getMethod()->getConfigData($fieldName);
+        return $method->getConfigData($fieldName);
     }
 
     /**

app/code/Magento/Payment/Gateway/Http/Converter/HtmlFormConverter.php

@@ -20,9 +20,13 @@ class HtmlFormConverter implements ConverterInterface
     public function convert($response)
     {
         $document = new \DOMDocument();
+
+        libxml_use_internal_errors(true);
         if (!$document->loadHTML($response)) {
             throw new ConverterException(__('Wrong gateway response format.'));
         }
+        libxml_use_internal_errors(false);
+
         $document->getElementsByTagName('input');
 
         $convertedResponse = [];