MAGETWO-33074: Upgrade response class.

Author: Sergey Semenov

app/code/Magento/PageCache/Model/Controller/Result/BuiltinPlugin.php

@@ -72,7 +72,7 @@ public function aroundRenderResult(
         }
 
         if ($this->state->getMode() == \Magento\Framework\App\State::MODE_DEVELOPER) {
-            $cacheControl = $response->getHeader('Cache-Control')['value'];
+            $cacheControl = $response->getHeader('Cache-Control')->getFieldValue();
             $response->setHeader('X-Magento-Cache-Control', $cacheControl);
             $response->setHeader('X-Magento-Cache-Debug', 'MISS', true);
         }

lib/internal/Magento/Framework/HTTP/PhpEnvironment/Response.php

@@ -21,7 +21,7 @@ class Response extends \Zend\Http\PhpEnvironment\Response implements \Magento\Fr
      * If header with specified name was not found returns false.
      *
      * @param string $name
-     * @return \Zend\Http\Header\Interface|bool
+     * @return \Zend\Http\Header\HeaderInterface|bool
      */
     public function getHeader($name)
     {