Ticket #8614: Default page cache path to the current request path

Currently, cache_page regenerates the cached path from the current params (controller, action, etc). By default, page should be cached at the path they are requested for (doesn't that only make sense?).

Example   map.root :controller => "welcome"   GET /

Caches output to "public/welcome/index.html" when we want it to be at "public/index.html".

http://dev.rubyonrails.org/ticket/8614

Applied.