This bugzilla has been removed from the release and needs to be reviewed and Triaged for another Target Release.
This works properly right now, I can select a flavor with 0GB disk and there are not warnings.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2017:1739