Workaround for odoo/odoo#3972 on group by in logistics requisition
Make related currency stored to be able to group by it
Also set store to currency field on Logistics Requisition Line
And logistics requisition line country_id deserve a store="True" too, to enter in group of groupable fields
Merge pull request #89 from yvaucher/8.0-fix-lr-group_by-state

Workaround for odoo/odoo#3972 on group by in logistics requisition