rpm: drop %systemd_dir

There's a standard %_unitdir macro for this purpose, shipped with
systemd-rpm-macros .

contrib/fedora/rpm/NetworkManager.spec

@@ -23,7 +23,6 @@
 %global obsoletes_ppp_plugin         1:1.5.3
 %global obsoletes_initscripts_updown 1:1.35.4
 
-%global systemd_dir %{_prefix}/lib/systemd/system
 %global nmlibdir %{_prefix}/lib/%{name}
 %global nmplugindir %{_libdir}/%{name}/%{version}-%{release}
 
@@ -684,7 +683,6 @@ Preferably use nmcli instead.
 %endif
 	-Dsession_tracking=systemd \
 	-Dsuspend_resume=systemd \
-	-Dsystemdsystemunitdir=%{systemd_dir} \
 	-Dsystem_ca_path=/etc/pki/tls/cert.pem \
 	-Ddbus_conf_dir=%{dbus_sys_dir} \
 	-Dtests=yes \
@@ -821,7 +819,6 @@ intltoolize --automake --copy --force
 	--with-ebpf=%{ebpf_enabled} \
 	--with-session-tracking=systemd \
 	--with-suspend-resume=systemd \
-	--with-systemdsystemunitdir=%{systemd_dir} \
 	--with-system-ca-path=/etc/pki/tls/cert.pem \
 	--with-dbus-sys-dir=%{dbus_sys_dir} \
 	--with-tests=yes \
@@ -914,7 +911,7 @@ make -k %{?_smp_mflags} check || :
 
 
 %pre
-if [ -f "%{systemd_dir}/network-online.target.wants/NetworkManager-wait-online.service" ] ; then
+if [ -f "%{_unitdir}/network-online.target.wants/NetworkManager-wait-online.service" ] ; then
     # older versions used to install this file, effectively always enabling
     # NetworkManager-wait-online.service. We no longer do that and rely on
     # preset.
@@ -1053,10 +1050,10 @@ fi
 %{_prefix}/lib/firewalld/zones/nm-shared.xml
 %endif
 # systemd stuff
-%{systemd_dir}/NetworkManager.service
-%{systemd_dir}/NetworkManager-wait-online.service
-%{systemd_dir}/NetworkManager-dispatcher.service
-%{systemd_dir}/nm-priv-helper.service
+%{_unitdir}/NetworkManager.service
+%{_unitdir}/NetworkManager-wait-online.service
+%{_unitdir}/NetworkManager-dispatcher.service
+%{_unitdir}/nm-priv-helper.service
 %dir %{_datadir}/doc/NetworkManager/examples
 %{_datadir}/doc/NetworkManager/examples/server.conf
 %doc NEWS AUTHORS README CONTRIBUTING.md TODO
@@ -1101,7 +1098,7 @@ fi
 %if %{with ovs}
 %files ovs
 %{nmplugindir}/libnm-device-plugin-ovs.so
-%{systemd_dir}/NetworkManager.service.d/NetworkManager-ovs.conf
+%{_unitdir}/NetworkManager.service.d/NetworkManager-ovs.conf
 %{_mandir}/man7/nm-openvswitch.7*
 %endif
 
@@ -1175,8 +1172,8 @@ fi
 %if %{with nm_cloud_setup}
 %files cloud-setup
 %{_libexecdir}/nm-cloud-setup
-%{systemd_dir}/nm-cloud-setup.service
-%{systemd_dir}/nm-cloud-setup.timer
+%{_unitdir}/nm-cloud-setup.service
+%{_unitdir}/nm-cloud-setup.timer
 %{nmlibdir}/dispatcher.d/90-nm-cloud-setup.sh
 %{nmlibdir}/dispatcher.d/no-wait.d/90-nm-cloud-setup.sh
 %{_mandir}/man8/nm-cloud-setup.8*