This fixes the zuul debug log's logrotate filename. We also increase the
rotation count to 30 daily logs for all zuul scheduler zuul processes
(this matches the old server).
We also create a /var/lib/zuul/backup dir so that status.json backups
have a location they can write to. We do this in the base zuul role
which means all zuul servers will get this dir. It doesn't currently
conflict with any of the cluster members' /var/lib/zuul contents so
should be fine.
Change-Id: I4709e3c7e542781a65ae24c1f05a32444026fd26
39f10b5fe5