Turns out Ansible can't be trusted to actually check the result
dictionary everywhere it expects one, so put the real exception text
into -vvv output too.
It's used at least by the copy module, even though the result is still
mostly a no-op. _remote_chmod() doesn't accept octal mode, it accepts
symbolic mode. So implement a symbolic parser in helpers.py.
Still needs a ton of work to emulate argument handling, shell selection,
and output emulation in every case. Unsurprisingly, Ansible documents
none of this.
David Wilson