Need to document how to run elastic-recheck CLIs to find breaks

[Matt Riedemann]

sdague fixed e-r with this: https://review.openstack.org/#/c/135404/

In asking how he found that out, it sounds like clarkb looked up the (private) cron job logs for e-r and saw the failures.

I asked if there is a way for a normal human :) to do this and clarkb pointed me at:

https://git.openstack.org/cgit/openstack-infra/system-config/tree/modules/elastic_recheck/manifests/init.pp#n26

This is the cron job command:

$graph_all_cmd = 'elastic-recheck-graph /opt/elastic-recheck/queries -o all-new.json && mv all-new.json all.json'

We should document how to do this locally in elastic-recheck so people can do this without bugging clarkb every time we think there is something wrong with e-r.