User password not encrypted

When sign in with Twitter for the first time and "Automatically register new users" is enabled the generated password is stored in plain text into the database. Then the user cannot login with the provided password.

I solved this including 'includes/password.inc' and using user_hash_password on 'twitter_signin/twitter_signin.module' line 156

require_once DRUPAL_ROOT . '/' . variable_get('password_inc', 'includes/password.inc');
$account->pass = user_hash_password($password);