cups: Fix missing installation of cups sysv init scripts

The packageconfig needs to be --disable-systemd as documented in
configure file for cups. With the current value "--without-systemd" the
SYSTEM_DIR variable ends up being set to "no"

It is caused by the --without-* section in configure file resulting in
eval with_$ac_useropt=no ;;

$ac_useropt is "systemd" causing the variable $with_systemd to be set
to "no", because of below test

if test ${with_systemd+y}
then :
  withval=$with_systemd; SYSTEMD_DIR="$withval"
else $as_nop
  SYSTEMD_DIR=""
fi

cups configure test for i if SYSTEMD_DIR is empty to decide if the init
scripts need to be installed. A value of "no" results in that no init
scripts is installed.

With --disable-systemd it works as expected - installing the init files.
Though cups should properly improve their configure script.

Signed-off-by: Claus Stovgaard <clst@ambu.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>