[Nut-upsuser] reset "replace battery" flag

[Roger Price]

On Mon, 21 Sep 2020, Lionel Élie Mamane wrote:

> We have a HP R/T 3000 G4 UPS; according to the data returned by the
> usbhid-ups driver, it seems to be a "badge engineered" Eaton 5PX UPS
> LI R 3000.
>
> We have a stubborn "Replace Battery" alarm that stays despite:
> ...
> The panel doesn't show any battery-related alarm.
>
> I initially "guessed" this was some kind of stale flag in some
> internal NUT database or cache, but I couldn't find on the hard disk
> where that is/was, and restarting all NUT daemons & drivers didn't
> help either.

The upsd daemon keeps an image of the current state of the UPS unit in memory. 
There is no external database.  The monitor daemon upsmon polls this image.

> Anybody has a clue how I should proceed or debug the issue?

At first sight this looks like a "feature" of the particular UPS unit you have, 
but perhaps other have deeper insight.

Roger