Fix miq_ae_datastore spec restore test.

@tinaafitz @mkanoor This seems ok to fix the test but is there a reason why we need to pass an actual zip file?  It might be nice to pass a dummy StringIO object (StringIO.new("--- dummy\n...\n")) to .restore with 'zip_file'=>nil and so we don't have to checkin a zip file. We can do that in follow up pull request.