Fix chromoting apt-config usage that breaks on Ubuntu 16.10.

remoting/host/installer/linux/debian/postrm

 #!/bin/bash
 
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 set -e
 
 if [ "$1" = "purge" ]; then
   delgroup --quiet chrome-remote-desktop > /dev/null || true
 fi
 
 APT_CONFIG="`which apt-config 2> /dev/null`"
 
-apt_config_val() {
-  APTVAR="$1"
-  if [ -x "$APT_CONFIG" ]; then
-    "$APT_CONFIG" dump | sed -e "/^$APTVAR /"'!d' -e "s/^$APTVAR \"\(.*\)\".*/\1/"
-  fi
-}
-
 # Only remove the defaults file if it is not empty. An empty file was probably
 # put there by the sysadmin to disable automatic repository configuration, as
 # per the instructions on the package download page.
 DEFAULTS_FILE="/etc/default/chrome-remote-desktop"
 if [ -s "$DEFAULTS_FILE" ]; then
   # Make sure the package defaults are removed before the repository config,
   # otherwise it could result in the repository config being removed, but the
   # package defaults remain and are set to not recreate the repository config.
   # In that case, future installs won't recreate it and won't get auto-updated.
   rm "$DEFAULTS_FILE" || exit 1
 fi
 # Remove Google repository added by the package.
-APTDIR=$(apt_config_val Dir)
-APTETC=$(apt_config_val 'Dir::Etc')
-APT_SOURCESDIR="$APTDIR$APTETC$(apt_config_val 'Dir::Etc::sourceparts')"
-rm -f "$APT_SOURCESDIR/chrome-remote-desktop.list"
+if [ -x "$APT_CONFIG" ]; then
+  eval $("$APT_CONFIG" shell APT_SOURCESDIR 'Dir::Etc::sourceparts/d')
+  rm -f "${APT_SOURCESDIR}chrome-remote-desktop.list"
+fi
 
 #DEBHELPER#