requested in newsyslog.conf. This was only the case using the non-time
based filenames (.0, .1, .2 etc.).
The change also makes newsyslog clean clean up the old extra logfile so
users don't end up with a single stale logfile which won't be rotated
out.
This change also cleans up some code a bit to avoid more copy / paste
code and removes some old copy / paste code in the process.
PR: bin/76697
MFC after: 2 weeks
449590b192