Optimize systemd dependency for containers

According to https://fedoraproject.org/wiki/Packaging:Scriptlets:
If a package is suitable for installation without systemd (in a
container image, for example) and does not require any of the
systemd mechanisms such as tmpfiles.d, then the systemd_ordering macro
MAY be used instead of the systemd_requires macro.

That is exactly the case we want to address for container images
when installing packages in it.

Resolves: rhbz#1654672
Related-Bug: #1804822
Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>

puppet.spec

@@ -104,7 +104,7 @@ Provides:       hiera-puppet = %{version}-%{release}
 
 Requires(pre):  shadow-utils
 %if 0%{?_with_systemd}
-%{?systemd_requires}
+%{?systemd_ordering}
 BuildRequires: systemd
 %else
 Requires(post): chkconfig
@@ -126,7 +126,7 @@ Group:          System Environment/Base
 Summary:        Server for the puppet system management tool
 Requires:       puppet = %{version}-%{release}
 %if 0%{?_with_systemd}
-%{?systemd_requires}
+%{?systemd_ordering}
 BuildRequires: systemd
 %else
 Requires(post): chkconfig