pbis-open does not install systemd services at first installation

When upgrading a 7.4 Xenserver to 7.5 via the updates ISO (which behind the scenes uses yum to update the packages) and comparing to a 7.5 fresh install, I see differences regarding pbis-open's service files.

After a fresh 7.5 install, I get a sysvInit service file, not systemd units :

/etc/rc.d/init.d/lwsmd

After the upgrade, I get systemd units instead.

/etc/systemd/system/lwsmd.service
/etc/systemd/system/multi-user.target.wants/lwsmd.service
/etc/systemd/system/nss-lookup.target.wants/
/etc/systemd/system/nss-lookup.target.wants/lwsmd.service

According to what I see in the spec file, it is probably a dependency ordering issue: if pbis-open gets installed before systemd, then in the %post scriptlet systemd is not detected and it falls back to initscripts. When the pbis-open package is upgraded, then systemd is detected and it switches to systemd units.

Proposed solution, add:

Requires(post): systemd

Or maybe better yet:

%systemd_requires

... which evaluates to:

$ rpm --eval %systemd_requires

Requires(post): systemd
Requires(preun): systemd
Requires(postun): systemd

(requires systemd as BuildRequires)

I hope my analysis is correct.