limit the "name2" for update sections in modules

limit the "name2" for update sections in modules

since we no longer support full-featured "update" sections, there
is no point in supporting full paths (outer, parent, etc.) in
update sections.  Plus, none of the modules use them.

So rather than either confusing the admin, or allowing them to do
something which might not work, we just return a compile-time
error.

The deleted code was also the only code (other then tests) that
called tmpl_request_ref_list_afrom_substr().  This cleanup will
allow us to fix the tmpl code for ""flat" groups