request #7589: Logrotate system event logs

We only keep one month of system logs.

Change-Id: Ia8931f6bf87f885046e83592978028c005b5237d
Merge commit 'refs/changes/79/3179/4' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #7589: Logrotate system event logs

Change-Id: I26bec1d937d7ce155b81161c2f576d41dee3de8f
This is Tuleap 7.6.99.48

Change-Id: Ic6232a90f16717da55f6c32db943e10ca21e26f6