Merge branch 'MAGETWO-33074' into MAGETWO-32690

Author: okarpenko

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

@@ -108,11 +108,8 @@ public function clearHeader($name)
     {
         $headers = $this->getHeaders();
         if ($headers->has($name)) {
-            foreach ($headers as $header) {
-                if (strtolower($header->getFieldName()) == strtolower($name)) {
-                    $headers->removeHeader($header);
-                }
-            }
+            $header = $headers->get($name);
+            $headers->removeHeader($header);
         }
 
         return $this;