Neuter sysusers macros

https://pagure.io/packaging-committee/pull-request/1436 was merged,
packaging guidelines describe the new method as the default option for f42+.

macros.sysusers

@@ -2,9 +2,9 @@
 #
 # Turn a sysusers.d file into macros specified by
 # https://docs.fedoraproject.org/en-US/packaging-guidelines/UsersAndGroups/#_dynamic_allocation
+#
+# After https://fedoraproject.org/wiki/Changes/RPMSuportForSystemdSysusers,
+# those macros are not needed anymore.
 
-%sysusers_requires_compat Requires(pre): shadow-utils
-
-%sysusers_create_compat() \
-%(%{_rpmconfigdir}/sysusers.generate-pre.sh %{?*}) \
-%{nil}
+%sysusers_requires_compat %nil
+%sysusers_create_compat() %nil