Enable an update to handle returned state

[NBIX-Mark-Southern]

My Odata system returns state from an update (PATCH) call. It makes sense to update the entity object with this and not need to make a separate call (force_refresh=True). The logic is the same as for an insert (POST) call.

As an aside, it may make sense to separate the save method into insert and update calls as in order to make an update without first having to query for an entity before updating it. To achieve this, I had to set Entity.__odata__.persisted = True which seems too obsure for a general pattern.

sample = odata_service.entities["SAMPLE"]()
sample.Barcode = "12345" # primary key
sample.HELLO = "world"    # property to update
sample.__odata__.persisted = True  # flag it already exists to force an update
odata_service.save(sample, force_refresh=False)