Minor: initialize variable and format code

main/inc/lib/agenda.lib.php

@@ -1621,6 +1621,7 @@ class Agenda
 
         $em = Database::getManager();
         $agendaCollectiveInvitations = api_get_configuration_value('agenda_collective_invitations');
+        $inviteeRepo = null;
         if ($agendaCollectiveInvitations) {
             $inviteeRepo = $em->getRepository('ChamiloCoreBundle:AgendaEventInvitee');
         }