This revises the test set for chmod to reflect OpenBSD behaviour.
Per discussion with dbussink at #1907 (comment)
OpenBSD chmod accepts all values of mode
What should be considered here is that Rubyspec specifies what MRI does. It means that the specs should always pass on MRI. Did you check whether the specs on MRI pass after these changes? If not, we probably need to setup deviates_on blocks for Rubinius if we behave different from MRI here.
Thanks. This should be closed because it breaks the spec for 1.8 and 1.9 MRI on OpenBSD. I'll investigate the fix you suggest.