getResponseMessage not using errorMap properly

[jonathanjfshaw]

    protected function getResponseMessage($data)
    {
        $error = 'An unknown error occurred with this request';
        if ($data !== null && isset($data['error'])) {
            if (isset($this->errorMap[$data['error']])) {
                $error = $data['error'];
            } else {
                $error = 'Unknown error code ' . $data['error'];
            }
        }

        return $error;
    }

The lookup in errorMap is not happening, and exception get messages like "invalid_grant".

$error = $data['error']; should be $error = $this->errorMap[$data['error']];