keep variant setting removed by previous commit
    
    to avoid error like:
    ===
    $~/createhdds/createhdds.py  support
    ...
    Traceback (most recent call last):
      File "/root/createhdds/createhdds.py", line 821, in <module>
        main()
      File "/root/createhdds/createhdds.py", line 811, in main
        args.func(args, hdds)
      File "/root/createhdds/createhdds.py", line 701, in cli_image
        img.create(args.textinst)
      File "/root/createhdds/createhdds.py", line 291, in create
        loctmp.format(fedoradir, str(self.release), variant, arch), "--name", "createhdds",
    NameError: name 'variant' is not defined
    ===
    
    Signed-off-by: Michel Normand <normand@linux.vnet.ibm.com>