Get rid of a warning for using an uninitialized variable.

git-svn-id: file:///tmp/wdn_thm_drupal/branches/drupal-7.x@67 20a16fea-79d4-4915-8869-1ea9d5ebf173

sites/all/themes/unl_wdn/template.php

@@ -128,6 +128,7 @@ function unl_wdn_menu_local_task($variables)
 
 function unl_wdn_status_messages($display)
 {
+    $output = '';
     foreach (drupal_get_messages($display) as $type => $messages) {
         $output .= '<div>' . PHP_EOL;
         if (count($messages) > 1) {