rename postrm to apt.postrm

It helps in identifying its affiliation.
Also removes the old postinst which was hidden by apt.postinst for a
long time now and would just install a sources.list in edgecases which
is probably not a good idea (e.g. on my system /etc/apt/sources.list
does not exist). It is better done by the installer of the distro.

Git-Dch: Ignore

debian/postinst

@@ -1,39 +0,0 @@
-#! /bin/sh
-
-# apt postinst, based liberally on James Troup's gpm postinst
-# Copyright (C) 1998, Ben Gertzfield <che@debian.org>
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-
-set -e
-
-create_apt_conf ()
-{
- EXAMPLE_SOURCE=/usr/share/doc/apt/examples/sources.list
- if [ -f $EXAMPLE_SOURCE ]; then
-     cp $EXAMPLE_SOURCE /etc/apt/sources.list
- fi
-}
- 
-check_apt_conf ()
-{
- true
- # this is for future expansion
-}
-
-#DEBHELPER#
-
-case "$1" in
-       configure)
-	       #
-               # If there is no /etc/apt/sources.list then create a default
-	       #
-	       if [ ! -f /etc/apt/sources.list ]; then
-	         create_apt_conf
-	       else
-	         check_apt_conf
-	       fi
-esac