systemd in RHEL/CentOS 7 lacks the same Directory directives that Debian 9 lacks

I tried installing kea 2.4 on CentOS 7 using yum and journalctl output reports that several "Directory" directives in the service unit files are not known to its old version of systemd. It looks like the kea source already has build code to deal with this for Debian 9 in hammer.py. (Search for LogsDirectory for the loop where these are removed.) More info on the directives:

https://serverfault.com/questions/1033129/centos-7-systemd-exec-configuration-alternatives-to-logsdirectory-cachedirect

I've reverted to kea 2.2 where these new directives are absent.

Here's the code in hammer.py that addresses this for Debian 9:

    # debian 9 does not support some fields in systemd unit files so they need to be commented out
    if system == 'debian' and revision == '9':
        for f in services_list:
            for k in ['RuntimeDirectory', 'RuntimeDirectoryPreserve', 'LogsDirectory', 'LogsDirectoryMode', 'StateDirectory', 'ConfigurationDirectory']:
                cmd = "sed -i -E 's/^(%s=.*)/#\\1/' %s" % (k, f)
                execute(cmd, cwd='kea-src/kea-%s/debian' % pkg_version, check_times=check_times, dry_run=dry_run)