Added hook when killing a session

CHANGELOG

@@ -1,6 +1,8 @@
 CHANGELOG RoundCube Webmail
 ===========================
 
+- Added hook when killing a session
+- Added hook to write_log function (#1485971)
 - Performance improvements by use UID commands (#1485690)
 - Fix HTML editor tabIndex setting (#1485972)
 - Added 'imap_debug' option

program/include/rcmail.php

@@ -797,6 +797,8 @@ class rcmail
    */
   public function kill_session()
   {
+    $this->plugins->exec_hook('kill_session');
+    
     rcube_sess_unset();
     $_SESSION = array('language' => $this->user->language, 'auth_time' => time(), 'temp' => true);
     rcmail::setcookie('sessauth', '-del-', time() - 60);