We don't use gksu, and it was the only reason we installed
gconf. Removing these packages + deps will not only save quite some
space (30 MiB installed) but will also remove a source of
non-determinism in the filesystem (element order in
/var/lib/gconf/defaults/%gconf-tree-*.xml) which made Tails
unreproducible.

We also remove:

* libgnomevfs2-extra, which was previously used for SSH/FTP support in
  Nautilus, but isn't needed for that any more.

* libgnome2-bin which provides gnome-open. We'll find a replacement
  for that in a later commit.

* Configurations and scripts that become obsolete because of these
  removals.

Will-fix: #12738