bug#15687: 24.3.50; custom themes: disabling does not restore initial configuration

[Drew Adams <drew.adams@oracle.com>]

> >> and the settings were apparently properly reset.  Do you have a recipe
> >> that triggers the problem?
> > You skipped the first part:
> 
> Maybe I did, but I have a limited amount of time.  So if you don't want
> to give me an actual detailed recipe I can't help you.

I gave a recipe.  I'll repeat it.

 emacs -Q, load oneonone.el, then doremi.el and
 doremi-cmd.el.  Then cycle among themes, using `doremi-custom-themes+'.
 Use `C-g' to cancel.  The initial state is not restored.  Nothing
 close to it.  Not for any existing frames.

And I pointed clearly to a performance problem.  Which you can also
easily see using that recipe.  And if you want to see what happens
to performance if you allow theme accumulation, just set option
`doremi-custom-themes-accumulate-flag' to t.  Bonjour les degats.

And you have it wrong.  You are not helping me.  I am helping you
(Emacs).  Trying to, anyway.  Same reason I provide such theme-cycling
commands - to help those who actually use themes (color or custom).
I, myself, do not use them.  But I still try to get them to work well.
For others.