This is a performance revision.
Some stored functions field were recomputed uselessly.
In mrp, `hour_total` and `cycle_total` were recomputed
at each write on `mrp.production`, while they should be recomputed
only when there is a change on the `workcenter_lines` field,
or when there is a change in the `hour` or `cycle` field
of these `workcenter_lines`.
In stock, `min_date`, `max_date` and `priority` of
`stock.picking` were recomputed each time a new move
was added to the picking,
wether or not the 'expected_date' of this move
was between the `stock.picking` `min_date` and `max_date`,
and the priority not greater.
In stock, `product_qty` of `stock.move` was recomputed
at each write on the `stock.move`, while it should be
recomputed only when there is a change in `product_id`,
`product_uom` or `product_uom_qty`, as the computation
method only depends on these three fields.
In stock_account, the `invoice_state` of `stock.picking`
was recomputed each time a new `stock.move` was associated
to the picking, wether or not the `invoice_state` of the move
was already the same than the `invoice_state` of the picking.
opw-643560