[FIX] mrp: quantity to consume lost

Process a workorder in the community version. Change the quantity to
produce. The quantity to consume is adapted for each component. Save the
workorder and the quantities to consume are rollbacked to the previous values

Those quantities are readonly so not saved to the server.

Task : 2127443

closes odoo/odoo#40557

Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>

addons/mrp/views/mrp_workorder_views.xml

@@ -161,7 +161,7 @@
                             <field name="product_tracking" invisible="1"/>
                             <field name="company_id" invisible="1"/>
                             <field name="lot_id" attrs="{'readonly': [('product_tracking', '=', 'none')]}" context="{'default_company_id': company_id, 'default_product_id': product_id, 'active_mo_id': parent.production_id}"/>
-                            <field name="qty_to_consume" readonly="1"/>
+                            <field name="qty_to_consume" readonly="1" force_save="1"/>
                             <field name="qty_reserved" readonly="1"/>
                             <field name="qty_done" attrs="{'column_invisible': [('parent.state', 'not in', ('progress', 'done'))]}"/>
                             <field name="product_uom_id" invisible="1"/>
@@ -175,7 +175,7 @@
                             <field name="product_tracking" invisible="1"/>
                             <field name="company_id" invisible="1"/>
                             <field name="lot_id" attrs="{'readonly': [('product_tracking', '=', 'none')]}" context="{'default_company_id': company_id, 'default_product_id': product_id}"/>
-                            <field name="qty_to_consume" readonly="1" string="To Produce"/>
+                            <field name="qty_to_consume" readonly="1" string="To Produce" force_save="1"/>
                             <field name="qty_done" string="Produced"/>
                             <field name="product_uom_id" invisible="1"/>
                             <field name="move_id" invisible="1"/>