Bug#1017446: debian-policy: stress that preinst script that install by using base64 decode on self an elf binary is not a good stuff

[Christoph Berg <myon@debian.org>]

Re: roucaries bastien
> The problem is the base64 encoded binary.

I agree that base64 there is weird, but does that really need an
explicit mention in the policy? If I were you, I'd just remove that
weirdness and move along.

Christoph