aliases are not validated in the validate step

I just found out that a domain name, that doesn't match the Fully Qualified Domain Name, is removed and ignored at insert operation in the hook_nodeapi. I think this is not correct because the user is not warned about the error.

I created a small patch that moves the _hosting_valid_fqdn function from the insert to validate, triggering a form_error when the prompted domain name is not valid.