Allow configuring the config drive
As cd drive and/or other formats like the default iso9660 format
diff --git a/nova/files/mitaka/nova-compute.conf.Debian b/nova/files/mitaka/nova-compute.conf.Debian
index 7e94913..9deff73 100644
--- a/nova/files/mitaka/nova-compute.conf.Debian
+++ b/nova/files/mitaka/nova-compute.conf.Debian
@@ -11,7 +11,8 @@
compute_manager=nova.compute.manager.ComputeManager
network_device_mtu=65000
use_neutron = True
-config_drive_format=vfat
+config_drive_format={{ compute.get('config_drive', {}).get('format', 'vfat') }}
+config_drive_cdrom={{ compute.get('config_drive', {}).get('cdrom', False)|lower }}
force_config_drive=True
security_group_api=neutron
vif_plugging_is_fatal=True