fix: [base] update debian 9 repository URL to archive for backports (to have ``fzf``)

precise/base-0k/hooks/install.d/30-customize.sh

@@ -43,13 +43,12 @@ if ! type -p fzf; then
             case $(lsb_release -rs) in
                 9|9.*)
                     backports_list="/etc/apt/sources.list.d/backports.list"
-                    if ! [ -e "$backports_list" ]; then
-                        echo "deb http://ftp.debian.org/debian stretch-backports main" > \
+                    protect_pre_install /etc/apt/sources.list.d/backports.list
+                    echo "deb http://archive.debian.org/debian stretch-backports main" > \
                              "$backports_list"
                     ## Update only this repo:
                     apt-get update -o Dir::Etc::sourcelist="sources.list.d/backports.list" \
                             -o Dir::Etc::sourceparts="-" -o APT::Get::List-Cleanup="0"
-                    fi
 
                     ;;
             esac