Unfortunately usage of `#update_attributes` had rolled over from a time
where `#update_attributes_with_options` was still in use and `opts` were
being passed in as an optional argument which had the result of further
nesting the hash internally (i.e. `:opts => { :opts => ... } }`).
This patch fixes that problem, adds a regression test to prevent it from
reappearing, and banishes the unused `#update_attributes_with_options`.
Fixes#334.
a014d505bc