Bug#864543: logrotate: use invoke-rc.d

[Christian Göttsche]

Package: apache2
Version: 2.4.25-3

Please use invoke-rc.d in the apache2 logrotate config instead of
directly calling /etc/init.d/apache2.
This will support systemd and is also mandatory in the upcoming policy
4.0.0 point 9.3.3.2 .