Move the tsocks binary out of the way.

We need to keep the tsocks package installed since ttdnsd needs its library, but
we drop the `/usr/bin/tsocks` binary so that users stop complaining about it not
being well configured.

config/chroot_local-hooks/42-remove_tsocks_binary

+#!/bin/sh
+
+set -e
+
+# Move any /usr/bin/tsocks installed by any package out of the way,
+# now (--rename) as well for any future one (hint: apt-get upgrade...).
+dpkg-divert --rename --add /usr/bin/tsocks