[Standards] Requirement for a replacement to iq:private

[Remko Tronçon]

> note that #3 can be achieved easily with something like XEP-0150 (ie. by
> sending a revision when requesting the xml file, and the server could return
> an error <up-to-date/> )

#3 can be achieved just as is done with other large PEP-related data:
use a #metadata node to store the hash, subscribe to the metadata, and
do a get on the #data node for retrieving the data itself.

cheers,
Remko