Fix override option on acme-bundle creation
Fix override option on acme-bundle creation

FileSystem->mirror function documentation explains this :

Valid options are:
     *                                 - $options['override'] Whether to override an existing file on copy or not (see copy())
HeahDude/SensioDistributionBundle,sensiolabs/SensioDistributionBundle,HeahDude/SensioDistributionBundle,sensiolabs/SensioDistributionBundle