[FIX] account_asset: inconsistencies deferred revenues and assets
[FIX] account_asset: inconsistencies deferred revenues and assets

The following configuration leads to different results:
- Deferred revenue: 12 entries, 1/month, prorata temporis, 1000€,
  date 15th of October
- Asset: 12 entries, 1/month, prorata temporis, 1000€, linear, date
  15th of October

Deferred revenues and assets should give identical results.

opw-690034

laslabs/odoo,hip-odoo/odoo,bplancher/odoo,dfang/odoo,hip-odoo/odoo,laslabs/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,hip-odoo/odoo,dfang/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,Elico-Corp/odoo_OCB,ygol/odoo,Elico-Corp/odoo_OCB,storm-computers/odoo,microcom/odoo,storm-computers/odoo,ygol/odoo,laslabs/odoo,Elico-Corp/odoo_OCB,dfang/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,storm-computers/odoo,laslabs/odoo,dfang/odoo,ygol/odoo,bplancher/odoo,microcom/odoo,microcom/odoo,laslabs/odoo,ygol/odoo,ygol/odoo,bplancher/odoo,microcom/odoo,bplancher/odoo,laslabs/odoo,hip-odoo/odoo,storm-computers/odoo,microcom/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,storm-computers/odoo,microcom/odoo,ygol/odoo,bplancher/odoo,dfang/odoo