Bug#390893: The apache2-common removal workaround

[sacrificial-spam-address@horizon.com]

Oh, I'm sorry it wasn't obvious.

The problem is that

1) apache2-common's prerm runs /etc/init.d/apache2 stop, which
2) runs /usr/sbin/apache2 -t, which
3) parses the config files, and does a full apache setup, which
4) tries to load all the modules, but
5) apache2-mpm-prefork has already been removed, so
6) it can't run.

Or, more simply, apache2-common's prerm Depends: on all the apache2 stuff,
and the fact that it isn't declared to causes a mess.

The simple workaround is to ensure that there are no apache2 processes
running (pgrep apache2), and then just comment the /etc/init.d/apache2 stop
call out of /var/lib/dpkg/info/apache2-common.prerm.

Actually, I just add "exit 0" before all the dh_installinit stuff.