simple-cdd - How to force deb installer to ask for host name

[Danny Brown <danbrwn@gmail.com>]

I know how to get the installer to set a host name to a string. But,
when I comment out the line like #d-i netcfg/get_hostname string. No
prompt ever is presented to enter the host name. So, my host name is
unassigned after install. I want a prompt to set the host name during
the install. I am using a preseed file