qapi: Make parameter 'file' optional for BlockdevCreateOptionsLUKS

To support detached LUKS header creation, make the existing 'file'
field in BlockdevCreateOptionsLUKS optional.

Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2 files changed