Bug#1055150: a2d: apt remove a2k nukes user data (postinst)

[Tobias Frost]

Package: a2d
Version: 2.0.1-1
Severity: serious
Justification: Policy 10.7.3

Found during package review:

postinst has:

#Remove user conf files
case "$1" in
    purge|remove|deconfigure|disappear)
        # Remove the user-generated configuration file
        if [ -e "/etc/a2d" ]; then
          rm -r /etc/a2d
        fi
        
        if [ -e "/var/lib/a2d" ]; then
          rm -r /var/lib/a2d
        fi

        if [ -e "/var/log/a2d_gu_error.log" ]; then
          rm -r /var/log/a2d_gu_error.log
        fi

        ;;

    *)
        # For other cases, do nothing
        ;;
esac

Multiple issues.
- Deleting user data is postinst must only done when purging.
- /etc/a2d is handled as conffile, it it dpkg's job to clean it up.
- /var/lib/a2d and /var/lib/a2d/dbs is also shipped with the package,
  and removing the directories should also be left to dpkg.
  (If possible the package should only delete the files it has
  created itself.)