cannot set sendmail section

I have set this on my `attributes/default.rb`:

```
default['gerrit']['sendemail']['smtpServer'] = 'smtp.mydomain.com'
default['gerrit']['sendemail']['smtpUser'] = 'gerrit'
default['gerrit']['sendemail']['from'] = 'Code Review <no-reply-gerrit@mydomain.com>'
```

on `gerrit.config`:

```
[sendemail]
    smtpServer = localhost
```
