[FIX][IMP] stock: set picking_warn as non required

When reinitializing modules it is impossible to create partners if
stock is installed because picking_warn field has a required column
but no default value if the module does not depend from stock. Use
case is trying to run test_mail tests with stock installed.

As this field is not business critical it is now not required. As there
is a default value behavior should not change for users.

addons/stock/models/res_partner.py

@@ -14,6 +14,6 @@ class Partner(models.Model):
     property_stock_supplier = fields.Many2one(
         'stock.location', string="Vendor Location", company_dependent=True,
         help="This stock location will be used, instead of the default one, as the source location for goods you receive from the current partner")
-    picking_warn = fields.Selection(WARNING_MESSAGE, 'Stock Picking', help=WARNING_HELP, default='no-message', required=True)
+    picking_warn = fields.Selection(WARNING_MESSAGE, 'Stock Picking', help=WARNING_HELP, default='no-message')
     # TDE FIXME: expand this message / help
     picking_warn_msg = fields.Text('Message for Stock Picking')

addons/stock/models/stock_picking.py

@@ -453,7 +453,7 @@ class Picking(models.Model):
             self.location_id = location_id
             self.location_dest_id = location_dest_id
         # TDE CLEANME move into onchange_partner_id
-        if self.partner_id:
+        if self.partner_id and self.partner_id.picking_warn:
             if self.partner_id.picking_warn == 'no-message' and self.partner_id.parent_id:
                 partner = self.partner_id.parent_id
             elif self.partner_id.picking_warn not in ('no-message', 'block') and self.partner_id.parent_id.picking_warn == 'block':

addons/stock/views/res_partner_views.xml

@@ -31,7 +31,7 @@
                     <separator string="Warning on the Picking" colspan="4"/>
                     <field name="picking_warn" nolabel="1" />
                     <field name="picking_warn_msg" colspan="3" nolabel="1" 
-                            attrs="{'required':[('picking_warn','!=','no-message')],'readonly':[('picking_warn','=','no-message')]}"/>
+                            attrs="{'required':[('picking_warn', '!=', False), ('picking_warn','!=','no-message')],'readonly':[('picking_warn','=','no-message')]}"/>
                 </group>
             </page>
         </field>