liveimg --url=file:/// failed with "ZeroDivisionError: float division by zero"

Issue

• liveimg kickstart command was supported in RHEL 7.1.
• I used the command with --url=file:///run/install/repo/image.tgz, I got the following python traceback.

anaconda 19.31.123-1 exception report
Traceback (most recent call first):
  File "/usr/lib64/python2.7/site-packages/pyanaconda/packaging/livepayload.py", line 207, in update
    pct = min(100, int(100 * bytes_read / self.size))
  File "/usr/lib/python2.7/site-packages/urlgrabber/grabber.py", line 1839, in _progress_update
    self.opts.progress_obj.update(downloaded)
ZeroDivisionError: float division by zero