[Fix] hr_employee: Fix compute fields

When we add a user to employee, we can have problem with leave,
expense or coach manager. It's due to those compute fields.

closes odoo/odoo#40795

Related: odoo/enterprise#6865
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>

addons/fleet/views/res_config_settings_views.xml

@@ -29,7 +29,7 @@
                                 <div class="o_setting_right_pane">
                                     <label for="module_fleet_account" string="Analytic Accounting"/>
                                     <div class="text-muted">
-                                        Manage analytic account for vehicle
+                                        Analyse vehicle costs with analytic accounting
                                     </div>
                                 </div>
                             </div>

addons/hr/models/hr_employee_base.py

@@ -86,3 +86,5 @@ class HrEmployeeBase(models.AbstractModel):
             previous_manager = employee._origin.parent_id
             if manager and (employee.coach_id == previous_manager or not employee.coach_id):
                 employee.coach_id = manager
+            elif not employee.coach_id:
+                employee.coach_id = False

addons/hr_expense/models/hr_employee.py

@@ -30,6 +30,8 @@ class Employee(models.Model):
             manager = employee.parent_id.user_id
             if manager and manager.has_group('hr_expense.group_hr_expense_user') and (employee.expense_manager_id == previous_manager or not employee.expense_manager_id):
                 employee.expense_manager_id = manager
+            elif not employee.expense_manager_id:
+                employee.expense_manager_id = False
 
 
 class EmployeePublic(models.Model):

addons/hr_holidays/models/hr_employee.py

@@ -158,6 +158,8 @@ class HrEmployeeBase(models.AbstractModel):
             manager = employee.parent_id.user_id
             if manager and employee.leave_manager_id == previous_manager or not employee.leave_manager_id:
                 employee.leave_manager_id = manager
+            elif not employee.leave_manager_id:
+                employee.leave_manager_id = False
 
     def _compute_show_leaves(self):
         show_leaves = self.env['res.users'].has_group('hr_holidays.group_hr_holidays_user')