Previously if a node did not have audit history data for each of the
windows over the tracking period, we would give them the benefit of
the doubt and set their score to 1. This was to prevent nodes from
being suspended right out the gate. We need a minimum amount of data
to evaluate them.
However, a node who is actually failing at being online will have no
idea until they have received enough audits and we suspend them.
Instead, we will always use their real score, but use a flag to determine
whether they are eligible for suspension/dq.
Change-Id: I382218f12e8770f95d4bcddcf101ef348940cadf
Add a function to the overlay cache called UpdateAuditHistory, which
allows us to add online or offline audits to a particular node's audit
history, and get that node's "online score" for the configured tracking
period.
The next step will be to use UpdateAuditHistory from inside
BatchUpdateStats/UpdateStats, so that audit history is actually updated
when nodes get audited, and we can suspend nodes based on their online
score.
Change-Id: I2289105e6961e68e829a987ff756b0e576fab120