[FIX] hr_holidays: Call onchange parent_id

Currently, parent_id is defined on hr.employee. This field
as an onchange defined.

But the inherit of hr.employee.base in the leave module
adds an onchange('parent_id'). The onchange method is never
called because the onchange in hr.employee does not call super
(which it's not supposed to do because the parent model
does not have the parent_id field).

To fix the issue, parent_id and all its onchange methods
are now defined on hr.employee.base

addons/hr/models/hr_employee.py

@@ -97,9 +97,7 @@ class HrEmployeePrivate(models.Model):
     image_1920 = fields.Image(default=_default_image)
     phone = fields.Char(related='address_home_id.phone', related_sudo=False, string="Private Phone", groups="hr.group_hr_user")
     # employee in company
-    parent_id = fields.Many2one('hr.employee', 'Manager', domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
     child_ids = fields.One2many('hr.employee', 'parent_id', string='Direct subordinates')
-    coach_id = fields.Many2one('hr.employee', 'Coach', domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
     category_ids = fields.Many2many(
         'hr.employee.category', 'employee_category_rel',
         'emp_id', 'category_id', groups="hr.group_hr_manager",
@@ -196,13 +194,6 @@ class HrEmployeePrivate(models.Model):
             if employee.pin and not employee.pin.isdigit():
                 raise ValidationError(_("The PIN must be a sequence of digits."))
 
-    @api.onchange('parent_id')
-    def _onchange_parent_id(self):
-        manager = self.parent_id
-        previous_manager = self._origin.parent_id
-        if manager and (self.coach_id == previous_manager or not self.coach_id):
-            self.coach_id = manager
-
     @api.onchange('job_id')
     def _onchange_job_id(self):
         if self.job_id:

addons/hr/models/hr_employee_base.py

@@ -26,6 +26,8 @@ class HrEmployeeBase(models.AbstractModel):
     user_id = fields.Many2one('res.users')
     resource_id = fields.Many2one('resource.resource')
     resource_calendar_id = fields.Many2one('resource.calendar', domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
+    parent_id = fields.Many2one('hr.employee', 'Manager', domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
+    coach_id = fields.Many2one('hr.employee', 'Coach', domain="['|', ('company_id', '=', False), ('company_id', '=', company_id)]")
     tz = fields.Selection(
         string='Timezone', related='resource_id.tz', readonly=False,
         help="This field is used in order to define in which timezone the resources will work.")
@@ -72,3 +74,10 @@ class HrEmployeeBase(models.AbstractModel):
             else:
                 employee.last_activity = False
                 employee.last_activity_time = False
+
+    @api.onchange('parent_id')
+    def _onchange_parent_id(self):
+        manager = self.parent_id
+        previous_manager = self._origin.parent_id
+        if manager and (self.coach_id == previous_manager or not self.coach_id):
+            self.coach_id = manager