Bug#836818: apache2: Better handling of obsoleting configuration files during the upgrade process in preinst script

[Erik Wasser <ewasser@maxcluster.de>]

Package: apache2
Version: 2.4.10-10+deb8u5
Severity: normal

Dear Maintainer,

is it possible to modify the function obsolete_conffile_exists() in the
`preinst' script?

I'm asking this with the following background: We're having the following
configuration files in our apache environment:

FILE  /etc/apache2/sites-available/default.conf
DIR   /etc/apache2/sites-available/default
FILES /etc/apache2/sites-available/default/*.conf

During the (jessie) upgrade process between 2.4.10-10+deb8u4 and
2.4.10-10+deb8u5 `our' directory `/etc/apache2/sites-available/default'
was renamed to `/etc/apache2/sites-available/default.dpkg-remove'.

The restart of the apache then failed because the configuration file
`/etc/apache2/sites-available/default/default.conf' still referenced to
the moved file/directory
`/etc/apache2/sites-available/default/default.conf'.

Please consider the following changes:

1) Replace the check against real files with `-f' instead of `-e'
(in the `preinst/obsolete_conffile_exists()' function).

2) Skip the whole obsolete-file-check if the upgrade is between
two apache 2.4.X instances.

Thanks for your help