Support Default Group for Users with LDAP authentication.

When Default Group for Users is enabled in Configure - Configuration - Authentication,
this default group can be used for all ldap users who use LDAP for authentication only,
for example, when an LDAP server does not have memberof attribute for groups.
    
https://bugzilla.redhat.com/show_bug.cgi?id=1060207

Instead of creating the opening tag twice, would it be cleaner to do

```erb
<div id="ldap_default_group_div" <%= 'style="display:none"' if @edit[:new][:authentication][:ldap_role] %> >
```

Then at least HTML editors won't complain about opening tags not matching closed tags.