xserver-nodm-init: install .service and conf only with systemd in DISTRO_FEATURES

* Otavio reported unpackaged files without systemd enabled

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
xinput-calibrator: install .service only with systemd in DISTRO_FEATURES

* Otavio reported unpackaged files without systemd enabled

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>