[FIX] base_location: Don't apply domain when cities are not enforced

And also reset city_id for avoiding incoherent information in that case.

Fixes #762

base_location/__manifest__.py

@@ -1,10 +1,10 @@
 # Copyright 2016 Nicolas Bessi, Camptocamp SA
-# Copyright 2018 Tecnativa - Pedro M. Baeza
+# Copyright 2018-2019 Tecnativa - Pedro M. Baeza
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
 {
     'name': 'Location management (aka Better ZIP)',
-    'version': '12.0.1.0.1',
+    'version': '12.0.1.0.2',
     'depends': [
         'base_address_city',
         'contacts',

base_location/models/res_partner.py

@@ -21,7 +21,7 @@ class ResPartner(models.Model):
                 'zip': False,
                 'city': False,
             })
-        if self.city_id:
+        if self.city_id and self.country_enforce_cities:
             return {
                 'domain': {
                     'zip_id': [('city_id', '=', self.city_id.id)]
@@ -49,6 +49,8 @@ class ResPartner(models.Model):
             if self.zip_id.city_id.state_id:
                 vals.update({'state_id': self.zip_id.city_id.state_id})
             self.update(vals)
+        elif not self.country_enforce_cities:
+            self.city_id = False
 
     @api.constrains('zip_id', 'country_id', 'city_id', 'state_id')
     def _check_zip(self):