Log Message:
Update ruby-rspec-mocks to 2.9.0.

### 2.9.0 / 2012-03-17
[full changelog](http://github.com/rspec/rspec-mocks/compare/v2.8.0...v2.9.0)

Enhancements

* Support order constraints across objects (preethiramdev)

Bug fixes

* Allow a `as_null_object` to be passed to `with`
* Pass proc to block passed to stub (Aubrey Rhodes)
* Initialize child message expectation args to match any args (#109 -
  preethiramdev)