[BUG] Touch release path after deploy

I've found a major bug while using this gem.

When deploying without ``-t`` in ``rsync_options`` all the modification time of the release directories are equals, since the rsync from the cache to the production use ``-a`` option.

The problem arise when running ``cap deploy:cleanup``: since all directory have the same timestamp, **the directory to delete are randomly selected**, not the oldest as it should be. In my scenario, this completely destroy the production.

A simple touch after deploy solves the problem.

I'm sorry I cannot create a test case, but I'm a Ruby newbie and Rake is complaining about deprecated libraries...