This call is useful for things like the search_indexer since there
is no ad_conn in a scheduled procedure
but in almost all other cases people should be using
[ad_conn package_id].
It throws an error if there are more than one package_id for a
given key since it should only be used for singletons -- maybe the query should explicitly check that and throw a more descriptive error.
It definitely not pick one of several at random!
In any case, I will add something to the proc docs to this effect.
