Comment 3 for bug 1644996

This bug doesn't exist in Debian, it's only Ubuntu related workaround for Ubuntu 14.04 (Trusty), see LP bug #1258202

logrotate (3.8.6-1ubuntu2) trusty; urgency=low
  * debian/logrotate.conf: use group 'syslog' by default when rotating logs,
    otherwise logrotate will refuse to rotate logs in /var/log whose owning
    group is now syslog instead of root. LP: #1258202.

 -- Steve Langasek <email address hidden> Thu, 05 Dec 2013 10:35:47 -0800

Ubuntu developers, please change /etc/logrotate.conf line
su root syslog
to
su root adm

Or maybe we can remove this line from /etc/logrotate.conf , because in Debian logrotate package there are no such line since 2013 ...