Update ruby-activerecord32 to 2.3.6.

## Rails 3.2.6 (Jun 12, 2012) ##

*  protect against the nesting of hashes changing the
    table context in the next call to build_from_hash. This fix
    covers this case as well.

    CVE-2012-2695

*  Revert earlier 'perf fix' (see 3.2.4 changelog / GH #6289). This
    change introduced a regression (GH #6609). assoc.clear and
    assoc.delete_all have loaded the association before doing the delete
    since at least Rails 2.3. Doing the delete without loading the
    records means that the `before_remove` and `after_remove` callbacks do
    not get invoked. Therefore, this change was less a fix a more an
    optimisation, which should only have gone into master.

    *Jon Leighton*

(taca)