apache2.pre-upgrade now links to apache2.pre-install.
It's not something we want to do for all packages in master (edge).
apache2 already had .pre-upgrade script (ensuring www-data group
existence and making apache user a member of it), which is what existing
.pre-install script also does, so this kind of unification is fine here.
In most other cases linking .pre-upgrade to .pre-install should happen
only in 3.4-stable branch.
Following rules have been applied:
- script starts with shebang !#/bin/sh followed by blank line,
- script ends with exit 0 prepended by blank line,
- only stderr of adduser, addgroup or passwd is redirected to /dev/null,
- getent passwd/group instances has been removed,
- manual checking of file and group existence has been removed,
- `|| true` instances has been removed.
Comments and line wrapping have been preserved.
