Use key().name() instead of link_id
This is now possible because key_name is constructed purely from the
key fields of an entity. It is not sufficient to use just link_id,
that works only for single-scoped entities (e.g., those that either
do not have a scope, or that have a scope which itself does not have
a scope). It would break if there was an entity that has a scoped
scope (it would only include the scope's link_id in the url, which
made it impossible to look up the scope as we missed the link_id of
the scope's scope).
Patch by: Sverre Rabbelier
