Default Promtail configuration includes /var/log

The default Promtail configuration winds up trying to ingest all logs on the host in /var/log. This seems a bit aggressive for the default and in a few cases, we saw Promtail not able to initially start due to OOMKilled errors. We got around this by pointing this to an empty directory /var/log/fake, as we really only care about what is in /var/log/pods in this case.