Add active field on extra

As the sale extra lines can not be deleted once linked to a sale line, there
should be a way to deactivate a sale extra.

issue4649
review8031002

sale.py

@@ -55,6 +55,7 @@ class SaleExtra(ModelSQL, ModelView, MatchMixin):
     __name__ = 'sale.extra'
 
     name = fields.Char('Name', translate=True, required=True)
+    active = fields.Boolean('Active')
     price_list = fields.Many2One('product.price_list', 'Price List',
         required=True, ondelete='CASCADE')
     sale_amount = fields.Numeric('Sale Amount',

view/extra_form.xml

@@ -4,8 +4,11 @@ this repository contains the full copyright notices and license terms. -->
 <form string="Extra">
     <label name="name"/>
     <field name="name"/>
+    <label name="active"/>
+    <field name="active"/>
     <label name="price_list"/>
     <field name="price_list"/>
+    <newline/>
     <label name="sale_amount"/>
     <field name="sale_amount"/>
     <field name="lines" colspan="4"

view/extra_list.xml

@@ -5,4 +5,5 @@ this repository contains the full copyright notices and license terms. -->
     <field name="price_list"/>
     <field name="name"/>
     <field name="sale_amount"/>
+    <field name="active" tree_invisible="1"/>
 </tree>