[FIX] crm: date_closed

When a lead is set to 'Won', the date_closed is defined. However, the
user might have clicked by mistake, and he might want to change the
state back. We need to take this into account, otherwise the lead is
considered as closed although it is not.

opw-674226

addons/crm/crm_lead.py

@@ -906,6 +906,8 @@ class crm_lead(format_address, osv.osv):
             vals.update(onchange_stage_values)
         if vals.get('probability') >= 100 or not vals.get('active', True):
             vals['date_closed'] = fields.datetime.now()
+        elif vals.get('probability') < 100:
+            vals['date_closed'] = False
         return super(crm_lead, self).write(cr, uid, ids, vals, context=context)
 
     def copy(self, cr, uid, id, default=None, context=None):