[FIX] hr_holidays: fix multi company issue in onchange

If you are logged into a company that differs from the company of your
employee, you won't be able to read the informations on that employee,
and you will have a crash.
Instead of taking the employee linked to the current user, we use search
in order to first apply the ir.rules hence we ensure that we will be
able to read the needed informations.

addons/hr_holidays/models/hr_leave.py

@@ -340,7 +340,7 @@ class HolidaysRequest(models.Model):
     def _onchange_type(self):
         if self.holiday_type == 'employee':
             if not self.employee_id:
-                self.employee_id = self.env.user.employee_ids[:1].id
+                self.employee_id = self.env['hr.employee'].search([('user_id', '=', self.env.uid)], limit=1).id
             self.mode_company_id = False
             self.category_id = False
         elif self.holiday_type == 'company':
@@ -353,7 +353,7 @@ class HolidaysRequest(models.Model):
             self.mode_company_id = False
             self.category_id = False
             if not self.department_id:
-                self.department_id = self.env.user.employee_ids[:1].department_id.id
+                self.department_id = self.env['hr.employee'].search([('user_id', '=', self.env.uid)], limit=1).department_id.id
         elif self.holiday_type == 'category':
             self.employee_id = False
             self.mode_company_id = False