build-support/vm: fix fillDiskWith* (#513033)

          echo "unpacking RPMs..."

          set +o pipefail

          for i in $rpms; do

          for i in "''${rpms[@]}"; do

              echo "$i..."

              ${rpm}/bin/rpm2cpio "$i" | chroot /mnt ${cpio}/bin/cpio -i --make-directories --unconditional

          done

          echo "installing RPMs..."

          PATH=/usr/bin:/bin:/usr/sbin:/sbin $chroot /mnt \

            rpm -iv --nosignature ${lib.optionalString (!runScripts) "--noscripts"} $rpms

            rpm -iv --nosignature ${lib.optionalString (!runScripts) "--noscripts"} "''${rpms[@]}"

          echo "running post-install script..."

          eval "$postInstall"

            memSize

            ;

          debs = (lib.intersperse "|" debs);

          debsFlat = lib.flatten debs;

          debsGrouped = debs;

          preVM = createEmptyImage { inherit size fullName; };

            # (which have lots of circular dependencies) from barfing.

            echo "unpacking Debs..."

            for deb in $debs; do

              if test "$deb" != "|"; then

            for deb in "''${debsFlat[@]}"; do

              echo "$deb..."

              dpkg-deb --extract "$deb" /mnt

              fi

            done

            # Make the Nix store available in /mnt, because that's where the .debs live.

            export DEBIAN_FRONTEND=noninteractive

            oldIFS="$IFS"

            IFS="|"

            for component in $debs; do

              IFS="$oldIFS"

            for component in "''${debsGrouped[@]}"; do

              echo

              echo ">>> INSTALLING COMPONENT: $component"

              debs=