Work around #1663040 in Workstation live installs
    
    We don't want the tests to fail on this now we know what the
    bug is, really - we want to find if there are any subsequent
    fails, and allow the post-install tests to run also. So, let's
    make it a soft failure.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>