XXX slapos/recipe/request: Optimize on detroy

XXX

It does not work as setting options['destroy-succeeded'] in the recipe
results with seeing destroy-succeeded in the .installed.cfg, but then
options.get('destroy-succeeded' ,'') always results with empty string,
and options['destroy-succeeded'] results with:

*** zc.buildout.buildout.MissingOption: Missing option: <section>:destroy-succeeded

Maybe it'll require some out-of-buildout place to store the state (file again?).