Use parted to rewrite the disklabel

Make an msdos disklabel, followed by a gpt disklabel, so we can
try to make sure the initial GPT label is gone

Change-Id: Iaaf40e8de8a4388c96c0a932a04d46d25501f177
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1158044
Signed-off-by: Ryan Barry <rbarry@redhat.com>