[FIX] base: keep the model cache consistent
[FIX] base: keep the model cache consistent

Do not remove fields from models except for custom fields.  Removing a base
field from a model screws up the model cache: that field may be required to
speed up the setup of the model in another registry.

Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,ygol/odoo,Elico-Corp/odoo_OCB,ygol/odoo,Elico-Corp/odoo_OCB,Elico-Corp/odoo_OCB,ygol/odoo,ygol/odoo,ygol/odoo