Fix XSS vulnerability in _mbox argument handling (#1490417)

Aleksander Machniak

2015-05-30 15fd8f9dc7e3919de5747a7bd3087be101daee5a

 program/include/rcmail.php

@@ -1820,7 +1820,7 @@
            }
            else {
                $error = 'servererrormsg';
                $args  = array('msg' => $err_str);
                $args  = array('msg' => rcube::Q($err_str));
            }
        }
        else if ($err_code < 0) {