'Detaches encrypted volumes attached to instance.'

def _detach_encrypted_volumes(self, instance, block_device_info):

    disks = self._get_instance_disk_info(instance, block_device_info)
    encrypted_volumes = filter(dmcrypt.is_encrypted, [disk['path'] for disk in disks])
    for path in encrypted_volumes:
        dmcrypt.delete_volume(path)
