Comment 15 for bug 392532

The output of

logrotate -d /etc/logrotate.conf

(run as root) would be interesting, too. Especially if it mentions errors or the file /etc/init.d/apache2.

BTW, you can restore the file with

cd /tmp
aptitude download apache2.2-common
dpkg --extract apache2.2-common_*.deb apache2.2-common
sudo cp apache2.2-common/etc/init.d/apache2 /etc/init.d

A normal reinstall is not enough because dpkg will think you have emptied the file intentionally. (Purging and installing again would work, but that would delete your whole apache configuration).