lithium: provision as syslog server

it has been provisioned with a 300G lv mounted on /srv/syslog.
/home/wikipedia/syslog is a symlink to /srv/syslog, I'll adjust the
centralserver role to reflect that in a separate change and when nfs1 is gone.

Change-Id: I94f4c1f342f4c40ffd6c76130df4a1c24393af21