Required change due to pykickstart bug 1367663.
The anaconda portion is this:
But that would probably be very different on rhel7-branch.
Conceptually, it's pretty easy to do though.
The fix is available in a pull request: https://github.com/rhinstaller/anaconda/pull/985
I was able to verify this bug on RHEL-7.4-20170421.1 with anaconda-18.104.22.168-1.el7.
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.