[FIX] purchase: Order date default value.

Using `fields.Date.context_today` for a `Date` field is the
right thing to do, but not for a `Datetime` field,
as it won't return the current hour, and this will lead
to issues with the different possible timezones.

opw-652391

addons/purchase/purchase.py

@@ -102,7 +102,7 @@ class PurchaseOrder(models.Model):
              "It's used to do the matching when you receive the "
              "products as this reference is usually written on the "
              "delivery order sent by your vendor.")
-    date_order = fields.Datetime('Order Date', required=True, states=READONLY_STATES, select=True, copy=False, default=fields.Date.context_today,\
+    date_order = fields.Datetime('Order Date', required=True, states=READONLY_STATES, select=True, copy=False, default=fields.Datetime.now(),\
         help="Depicts the date where the Quotation should be validated and converted into a purchase order.")
     date_approve = fields.Date('Approval Date', readonly=1, select=True, copy=False)
     partner_id = fields.Many2one('res.partner', string='Vendor', required=True, states=READONLY_STATES, change_default=True, track_visibility='always')