Comment # 1 on bug 1127610 from Giacomo Comes

The proposed fix has been included in the latest 15.1 Beta and the bug I
reported has been fixed.
However, now I found this error in /var/log/zypp/history:

# 2019-03-22 18:26:16 unbound-anchor-1.6.8-lp151.6.1.x86_64.rpm installed ok
# Additional rpm output:
# /var/tmp/rpm-tmp.XJP8nX: line 1: systemd-tmpfiles: command not found
# 
2019-03-22
18:26:17|install|unbound-anchor|1.6.8-lp151.6.1|x86_64||openSUSE-Leap-15.1-1|5e49024290ca886d97ed5133611d5cbdc6fda384a2755db2f7944ced90177d39|

This time the problem is with systemd-tmpfiles not available because
unbound-anchor is installed before systemd.
The fix is the following one:

 %package anchor
 #
 Summary:        Unbound Anchor cert management tools
 Group:          Productivity/Networking/DNS/Servers
 Requires(pre):  shadow
+%if %{with systemd}
+Requires(pre):  systemd
+%endif