How to keep files for failed run?

[ineu]

In https://github.com/sorah/hocho/blob/master/lib/hocho/drivers/ssh_base.rb#L48 there's the check for keep_synced_files which is not defined anywhere. Looks like this feature didn't survive dec1dab2ac49fa5eca093c8c511bbd336ca3884d and f4a45769e7c37f675ffe7bd86e75129accc7e840. Though it would be great to have: sometimes debugging on an actual server is the only way to go.

If you are ok with such feature I'm willing to submit a PR.

[sorah]

--keep-synced-files flag sounds good and I'm happy to review and accept a PR.