Upgrade to Rails 2.2.0

As a side benefit, fix an (non-user-visible) bug in display_s5().
Also fixed a bug where removing orphaned pages did not expire cached summary pages.

vendor/rails/actionpack/lib/action_pack/version.rb

@@ -1,8 +1,8 @@
 module ActionPack #:nodoc:
   module VERSION #:nodoc:
     MAJOR = 2
-    MINOR = 1
-    TINY  = 1
+    MINOR = 2
+    TINY  = 0
 
     STRING = [MAJOR, MINOR, TINY].join('.')
   end