Make sure prefs always is a valid array (otherwise causes fatal errors if language if not set)

program/lib/Roundcube/rcube_user.php

@@ -125,8 +125,10 @@ class rcube_user
      */
     function get_prefs()
     {
+        $prefs = array();
+
         if (!empty($this->language))
-            $prefs = array('language' => $this->language);
+            $prefs['language'] = $this->language;
 
         if ($this->ID) {
             // Preferences from session (write-master is unavailable)