Do not hard-require systemd as crond is used in containers without systemd

(#1654659)

cronie.spec

@@ -6,7 +6,7 @@
 Summary:   Cron daemon for executing programs at set times
 Name:      cronie
 Version:   1.5.2
-Release:   3%{?dist}
+Release:   4%{?dist}
 License:   MIT and BSD and ISC and GPLv2+
 Group:     System Environment/Base
 URL:       https://github.com/cronie-crond/cronie
@@ -32,10 +32,13 @@ BuildRequires:    systemd
 Obsoletes:        %{name}-sysvinit
 
 Requires(post):   coreutils sed
-Requires(post):   systemd
-Requires(preun):  systemd
-Requires(postun): systemd
-Requires(post):   systemd
+
+%if 0%{?fedora} && 0%{?fedora} < 28 || 0%{?rhel} && 0%{?rhel} < 8
+%{?systemd_requires}
+%else
+%{?systemd_ordering} # does not exist on Fedora27/RHEL7
+%endif
+
 
 %description
 Cronie contains the standard UNIX daemon crond that runs specified programs at
@@ -206,6 +209,10 @@ exit 0
 %attr(0644,root,root) %config(noreplace) %{_sysconfdir}/cron.d/dailyjobs
 
 %changelog
+* Fri Nov 30 2018 Tomáš Mráz <tmraz@redhat.com> - 1.5.2-4
+- Do not hard-require systemd as crond is used in containers without
+  systemd (#1654659)
+
 * Wed Oct 31 2018 Tomáš Mráz <tmraz@redhat.com> - 1.5.2-3
 - use role from the current context for system crontabs (#1639381)