Fix $http_response_header deprecation

Signed-off-by: Liviu-Mihail Concioiu <liviu.concioiu@gmail.com>

Author: liviuconcioiu

libraries/classes/Utils/HttpRequest.php

@@ -267,6 +267,10 @@ private function fopen(
             stream_context_create($context)
         );
 
+        if (function_exists('http_get_last_response_headers')) {
+            $http_response_header = http_get_last_response_headers();
+        }
+
         if (! isset($http_response_header)) {
             return null;
         }