[trunk/7.0/6.1] mrp: production location should be taken first from routing

By default, when confirming a manufacturing order, OpenERP creates consume and produce moves in _make_production_produce_line and _make_production_consume_line methods. These methods take production location from each product's "default production location" field.

IMHO, if the production has a routing assigned, and the routing was defined with a specific production location, this location should be the first choice production location. The field for the default production location in the product's form is useful when you don't want to specify a production location for a routing. But mrp.routing_id.location_id should always be the first option (if defined).

Maybe this issue is (conceptually) slightly related to bug #1249258, since neither in that bug the production location for a particular manufacturing order's routing wasn't kept into account, which in that case derived into a bug related to subcontracted manufacturing.

I attached a proposed enhancement patch.