Control: found -1 0.11.2-2 Control: found -1 0.10.2-2.1Control: retitle -1 logrotate should be silent if package is in removed state
Control: tags -1 + confirmed
That the file is left behind by a remove is not a bug in itself, because only a purge would delete it. But the logrotate configuration is missing this check in the postrotate section:
test -x /usr/bin/fail2ban-client || exit 0
