Remove duplicate country field definition in tariff code

The CountryMatchMixin already defines a country and an organization field.

modules/customs/customs.py

@@ -47,8 +47,6 @@ class TariffCode(DeactivableMixin, CountryMatchMixin, ModelSQL, ModelView):
     code = fields.Char('Code', required=True,
         help='The code from Harmonized System of Nomenclature.')
     description = fields.Char('Description', translate=True)
-    country = fields.Many2One('country.country', 'Country')
-    # TODO country group
     start_month = fields.Many2One('ir.calendar.month', "Start Month",
         states={
             'required': Eval('end_month') | Eval('start_day'),

modules/customs/view/duty_rate_form.xml

@@ -8,9 +8,9 @@ this repository contains the full copyright notices and license terms. -->
     <field name="type"/>
 
     <label name="country"/>
-    <field name="country"/>
+    <field name="country" colspan="3"/>
     <label name="organization"/>
-    <field name="organization"/>
+    <field name="organization" colspan="3"/>
 
     <label name="start_date"/>
     <field name="start_date"/>

modules/customs/view/tariff_code_form.xml

@@ -10,9 +10,10 @@ this repository contains the full copyright notices and license terms. -->
     <field name="description" colspan="3"/>
 
     <label name="country"/>
-    <field name="country"/>
+    <field name="country" colspan="3"/>
+
     <label name="organization"/>
-    <field name="organization"/>
+    <field name="organization" colspan="3"/>
 
     <label id="from" string="From"/>
     <group id="start" col="2">