Log Message:
Update ruby-activesupport to 2.3.8.  Patch by Wen Heping in PR 43425.

Changes since 2.3.5:
* HTML safety: fix compatibility with the optional rails_xss plugin.
  [Nathan Weizenbaum, Santiago Pastorino]
* 1.9 compat: deprecated last_(month|year) in favor of
  prev_(month|year). [fxn]
* Deprecated Array#rand in favor of Array#random_element. [Santiago
  Pastorino, Rizwan Reza]
* Added Object#presence that returns the object if it's #present?
  otherwise returns nil [DHH/Colin Kelley]
* New assertions assert_blank and assert_present.  #4299 [Juanjo Bazan]
* Use Object#singleton_class instead of #metaclass. Prefer Ruby's
  choice.  [Jere my Kemper]
* JSON backend for YAJL. Preferred if available.  #2666 [Brian Lopez]
* Introduce String#html_safe for rails_xss plugin and
  forward-compatibility with Rails 3.  [Michael Koziarski, Santiago
  Pastorino, José Ignacio Costa]
* Time#- with a DateTime argument behaves the same as with a Time
  argument, i.e.  returns the difference between self and arg as a
  Float #3476 [Geoff Buesing]
* YAML serialization for OrderedHash.  #3608 [Gregor Schmidt]
* Add Enumerable#exclude? to bring parity to Enumerable#include? and
  avoid if !x .include?/else calls [DHH]