icon cache scriplet guideline update

[Bill Nottingham]

Jason L Tibbitts III (tibbs at math.uh.edu) said: 
> MC> It is interesting to note that this proposal doesn't actually
> MC> address the one problem that there is with the current snipplets,
> MC> namely that we keep regenerating the cache over and over.
> 
> Well, the xdg script could do that.  We certainly shouldn't push such
> logic into the scriptlets of every package.

You seriously want a script to be handling per-transaction state of the
updater that's running it? That sounds like a very wrong solution.

Bill