Users sometimes define custom models on SQL views
e.g. @nseinlet
In such a case, Odoo should not attempt to create foreign keys
as it just cannot work on views.

This could prevent the migration of a database
with such a custom model using a view
when it attempted to fix the missing foreign keys
when updating the modules.

closes odoo/odoo#38951

Signed-off-by: Christophe Simonis <chs@odoo.com>