[FIX] mail: mark as read: notify correct partner

When calling 'set_message_done' on a message which is a needaction for several
partners, the method was executed as root. This was an issue for the triggered
notification, as it was thus always sent to the admin.

For example, when Demo user marked such a message as read, he never received
the notification, but the Admin did, and its notification counter weirdly
decreased, while the one of Demo user remained the same.

addons/mail/models/mail_message.py

@@ -197,10 +197,12 @@ class Message(models.Model):
             partners in partner_ids if partner_ids is given. """
         if not partner_ids:
             partner_ids = [self.env.user.partner_id.id]
+        new_value = {'needaction_partner_ids': [(3, pid) for pid in partner_ids]}
         if set(partner_ids) == set([self.env.user.partner_id.id]):
             # a user should be able to mark a message as done for him
-            self = self.sudo()
-        self.write({'needaction_partner_ids': [(3, pid) for pid in partner_ids]})
+            self.sudo().write(new_value)
+        else:
+            self.write(new_value)
 
         channel_ids = [c.id for c in self.channel_ids]
         notification = {'type': 'mark_as_read', 'message_ids': [self.id], 'channel_ids': channel_ids}