Replace outdated systemd-units

systemd-units was defining the %{_unitdir} macro. On Fedora 18 and newer,
the systemd-units subpackage has been merged into the base systemd package,
so a package for those targets should instead include: BuildRequires: systemd.
Later this was also changed to: BuildRequires: systemd-rpm-macros.

https://docs.pagure.org/packaging-guidelines/Packaging:Systemd.html
https://docs.fedoraproject.org/en-US/packaging-guidelines/Systemd/
Signed-off-by: Vladis Dronov <vdronov@redhat.com>

rng-tools.spec

@@ -12,7 +12,7 @@
 Summary:        Random number generator related utilities
 Name:           rng-tools
 Version:        6.11
-Release:        2%{?dist}
+Release:        3%{?dist}
 License:        GPLv2+
 URL:            https://github.com/nhorman/rng-tools
 Source0:        https://github.com/nhorman/rng-tools/archive/v%{version}/rng-tools-%{version}.tar.gz
@@ -22,7 +22,7 @@ Source1:        rngd.service
 
 BuildRequires: gcc make
 BuildRequires: gettext
-BuildRequires: systemd-units
+BuildRequires: systemd systemd-rpm-macros
 BuildRequires: libgcrypt-devel
 BuildRequires: autoconf automake
 BuildRequires: libsysfs-devel libcurl-devel
@@ -36,9 +36,9 @@ BuildRequires: rtl-sdr-devel
 BuildRequires: libp11-devel
 %endif
 
-Requires(post): systemd-units
-Requires(preun): systemd-units
-Requires(postun): systemd-units
+Requires(post): systemd
+Requires(preun): systemd
+Requires(postun): systemd
 Provides: jitterentropy-rngd
 
 %description
@@ -85,6 +85,9 @@ install -Dt %{buildroot}%{_unitdir} -m0644 %{SOURCE1}
 %attr(0644,root,root)   %{_unitdir}/rngd.service
 
 %changelog
+* Tue Mar 02 2021 Vladis Dronov <vdronov@redhat.com> - 6.11-3
+- Replace outdated systemd-units
+
 * Tue Mar 02 2021 Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> - 6.11-2
 - Rebuilt for updated systemd-rpm-macros
   See https://pagure.io/fesco/issue/2583.