qemu-img info: show nocow info
Add nocow info in 'qemu-img info' output to show whether the file currently has NOCOW flag set or not. Signed-off-by:Chunyan Liu <cyliu@suse.com> Reviewed-by:
Eric Blake <eblake@redhat.com> Signed-off-by:
Stefan Hajnoczi <stefanha@redhat.com>