Skip user/workstation setting updates when the value is unchanged

[Jeff Davis]

EG 3.5+

When applying a user or workstation setting update, the client should check whether the setting value has actually changed. If not, skip the server-side update, since it's superfluous.

For example, circ.checkin.strict_barcode and circ.checkin.do_inventory_update are set on each checkin, since the values can change between checkins. But most commonly you'll have dozens or hundreds of checkins in a row where those settings don't change. We should check whether the value has changed before doing dozens or hundreds of unnecessary calls to open-ils.actor.settings.apply.user_or_ws.

[Jeff Davis (jdavis-sitka)]

Attempted a fix in working branch user/jeffdavis/lp1901247-skip-user-ws-setting-updates but was unsuccessful. More work required. Unassigning myself in case someone else wants to take a shot.

[Bill Erickson (berick)]

Jeff, one suggestion is to use: "if (key in cache) { ... }" instead of "if (cache[key])" since many of the cached values may be null, false, or zero.