Rotate gearman log worker logs.

* modules/openstack_project/manifests/logstash_worker.pp: Use logrotate
to rotate Jenkins log worker logs. These log files were not being
rotated and get fairly large making debugging failures difficult. Rotate
the logs to simplify debugging with logs and prevent unbounded log
growth.

Change-Id: Ic7e983c1b88ea45430c732c0dadb0ba3f08c6cc6
Merge "Rotate gearman log worker logs."