Harmonize currency conversion of unit prices:
* Make sure no rounding is applied during the conversion
(it'll be managed by the price_unit decimal precision
and the currency rounding will only be applied by the
monetary fields later in the computations).
* consistent parameters for the conversion (date,
company, currency).
* code simplification
* consistent behavior when the SO has no currency specified
...
Part-of: odoo/odoo#110833
Victor Feyens
f938f00877