Issue #3182088: Warning function findTemplate should be compatible with parent function

Closes #3182088

src/Template/Loader/Loader.php

@@ -77,7 +77,7 @@ class Loader extends \Twig_Loader_Filesystem {
   /**
    * {@inheritdoc}
    */
-  protected function findTemplate($name) {
+  protected function findTemplate($name, $throw = TRUE) {
     if (is_null($this->components)) {
       // Scan the directory for any twig files and register them.
       // TODO: inherit components from base theme.