Update-settings-php doesn't work with Drush 13

[aOelschlager]

I was testing the Drush 13 pr for the starter-site and the update-settings.php make function is no longer working. When I removed that call and just use the same default_settings.txt and environment variables as the isle-site-template it worked. Perhaps this would be a good time to change this function to be more inline with how the isle-site-template implements the settings.php file.