Don't graph offsets when the server returned KoD

[abh]

1. track in the monitor more explicitly that a kiss code was returned

2. don't use KoD offsets when graphing

(alternatively don't log the offset when a KissCode was returned)

https://community.ntppool.org/t/do-not-use-offset-value-from-kod-responses-in-offset-score-graphs/2988/

[hart-NTP]

In a sense, a KoD RATE response is similar to a lack of response -- it provides no time information. In another sense, it's distinct, as it indicates there is a functioning NTP server responding in a timely, if useless, fashion.

Perhaps for scoring purposes it would make sense to treat a RATE response as a milder negative bump than a lack of response, and for offset graphing purposes, treat it similarly to a a non-response, that is, no offset data to graph.