class_inheritable_accessor is removed in Rails 3.2

Use class_attribute instead

--HG--
extra : rebase_source : 92ab6f38f4f5744a335273207247c030223994a0
inheritable_attributes are now class_attributes

--HG--
extra : rebase_source : d41fc53705be6d1f234648975a8097b3fc6b0f6f
SecureRandom moved to the top-level scope in Rails3

--HG--
extra : rebase_source : 781b3081eaaa17f96129896944bd14a1cde820b1
Revert "not run MySQL2 tests on Rails 3.0"