[CentOS] CentOS 7: System log has repeated lines: Started session 123 of user root.

Tue Jul 19 00:35:12 UTC 2016
therbur <fxb7-ox9n at dea.spamcon.org>

The system log (/var/log/messages) of a CentOS 7.2 system has
frequently-repeated message line pairs like:

Jul 18 14:00:01 localhost systemd: Started Session 307 of user root.
Jul 18 14:00:01 localhost systemd: Starting Session 307 of user root.

where the session number increases each time.

Looking around on this, e.g. Red Hat Bugzilla bug 727315, it looks like
it's when crond starts a task; it looks like it might be fixed - I would
think that would be in CentOS but don't know how to find/compare the
Fedora and CentOS systemd versions to know for sure.

I found a post on a workaround - in /etc/systemd/system.conf to change the
line:

#LogLevel=info

to:

LogLevel=notice

I did that and rebooted, and it has stopped the messages.

I'm worried though that this may have knocked out something of actual
interest from the syslog.

So my question is, is there a better way?  A way that info messages could
go to some other log, or better yet, a way that those particular "session"
messages, and only those, could go to some other log or be filtered out?