Impacted versions: all

On the model "ir.model.field" there is a field called "copy" : https://github.com/odoo/odoo/blob/master/odoo/addons/base/models/ir_model.py#L322

This name conflict with the method "copy" that exist browse record
https://github.com/odoo/odoo/blob/master/odoo/models.py#L4203

This make impossible to use the method copy on ir.model.field
And also raise warning when we make an inherits of the class ir.model.field (https://github.com/odoo/odoo/blob/master/odoo/models.py) as the field conflict with the method name

@odony @rco-odoo 

odoo/addons/test_new_api/tests/test_schema.py
self.assertTrue(field.column2)
        columns_data = self.get_columns_data(model._table)
        self.assertNotIn('categories', columns_data)
        table_data = self.get_table_data(field.relation)
        self.assertEqual(table_data, {
            'is_insertable_into': u'YES',
            'is_typed': u'NO',
            'table_catalog': self.cr.dbname,
            'table_name': u'test_new_api_discussion_category',
            'table_schema': u'public',
            'table_type': u'BASE TABLE',
            'user_defined_type_catalog': None,
            'user_defined_type_name': None,
            'user_defined_type_schema': None,
        })
        columns_data = self.get_columns_data(field.relation)
        self.assertEqual(columns_data, {
            field.column1: {
                'character_maximum_length': None,
                'column_default': None,
                'column_name': u'discussion',
                'data_type': u'integer',
                'datetime_precision': None,
                'is_nullable': u'NO',
                'is_updatable': u'YES',
                'numeric_precision': 32,
                'numeric_precision_radix': 2,
                'numeric_scale': 0,
                'table_catalog': self.cr.dbname,
                'table_name': u'test_new_api_discussion_category',