oggz-tools: oggz-chop does not reset the timer in the chunk version graph

This was initially reported in https://bugs.debian.org/592759 2010-08-12 by Vlatko Šurlan.

When oggz-chop chops a chunk the chunks timer is not reset to starting at 0. I verified the behaviour by chopping last 5 minutes of a 15 minute chunk and the timer would run from 10:00 to 15:00. Also when I tried to upload the chunk to the YouTube it was rejected as being 15 minutes even though it was exactly 5 minutes long.