[FIX] stock: procurement generated by scheduler truncate datetime

When purchase order are created from a scheduler they always
have the same hours even if they were created at different
time. Also the procurement order that generate the purchase
order line have the same problem.

It happens because the transformation from datetime to string
use a date format and thus truncate the DEFAULT_SERVER_TIME_FORMAT

This commit use a datetime format instead the dateformat.

opw-775833

addons/stock/models/stock_warehouse.py

@@ -8,7 +8,7 @@ from dateutil import relativedelta
 from odoo import api, fields, models, _
 from odoo.addons import decimal_precision as dp
 from odoo.exceptions import UserError, ValidationError
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT
+from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT
 
 import logging
 
@@ -843,7 +843,7 @@ class Orderpoint(models.Model):
             # These days will be substracted when creating the PO
             days += self.product_id._select_seller().delay or 0.0
         date_planned = start_date + relativedelta.relativedelta(days=days)
-        return date_planned.strftime(DEFAULT_SERVER_DATE_FORMAT)
+        return date_planned.strftime(DEFAULT_SERVER_DATETIME_FORMAT)
 
     @api.multi
     def _prepare_procurement_values(self, product_qty, date=False, group=False):