[FIX] hr: extend employee privacy protection to a few fields

A few fields present in the "Private Info" tab of the Employee form did
not have the corresponding `groups` attribute.
This could cause access rights problems.

addons/hr/models/hr.py

@@ -111,9 +111,10 @@ class Employee(models.Model):
     active = fields.Boolean('Active', related='resource_id.active', default=True, store=True)
     # private partner
     address_home_id = fields.Many2one(
-        'res.partner', 'Private Address', help='Enter here the private address of the employee, not the one linked to your company.')
+        'res.partner', 'Private Address', help='Enter here the private address of the employee, not the one linked to your company.',
+        groups="hr.group_hr_user")
     country_id = fields.Many2one(
-        'res.country', 'Nationality (Country)')
+        'res.country', 'Nationality (Country)', groups="hr.group_hr_user")
     gender = fields.Selection([
         ('male', 'Male'),
         ('female', 'Female'),
@@ -135,9 +136,9 @@ class Employee(models.Model):
         domain="[('partner_id', '=', address_home_id)]",
         groups="hr.group_hr_user",
         help='Employee bank salary account')
-    permit_no = fields.Char('Work Permit No')
-    visa_no = fields.Char('Visa No')
-    visa_expire = fields.Date('Visa Expire Date')
+    permit_no = fields.Char('Work Permit No', groups="hr.group_hr_user")
+    visa_no = fields.Char('Visa No', groups="hr.group_hr_user")
+    visa_expire = fields.Date('Visa Expire Date', groups="hr.group_hr_user")
 
     # image: all image fields are base64 encoded and PIL-supported
     image = fields.Binary(