[FIX] portal: Portal user not able to update their details

Steps to reproduce the bug:

- Create a portal user U
- Try to update the details of U from portal

Bug:

A server error was raised because the country_id was set as a character.

opw:2082450

closes odoo/odoo#38795

Signed-off-by: Simon Goffin (sig) <sig@openerp.com>

addons/portal/controllers/portal.py

@@ -174,6 +174,7 @@ class CustomerPortal(Controller):
             if not error:
                 values = {key: post[key] for key in self.MANDATORY_BILLING_FIELDS}
                 values.update({key: post[key] for key in self.OPTIONAL_BILLING_FIELDS if key in post})
+                values.update({'country_id': int(values.pop('country_id', 0))})
                 values.update({'zip': values.pop('zipcode', '')})
                 if values.get('state_id') == '':
                     values.update({'state_id': False})