Integration tests and fixes for rsync/scp transfer actions.

 - Rearrange things so ssh_key can be alternatively defined in file_actions.yml or the other properties ssh_user, ssh_host, ssh_port can be defined in destination_params. This allows these actions to be usable as the default file action and made it much easier to test.
 - Fixes when constructing scp command-line (my version of Python didn't like a tuple in middle of subprocess.check_call).
 - Increase integration test timeout (these are slower than localhost RESTful transfer).
 - Add integration test for each of these commands.