Log Message:
Update ruby-net-ssh to 2.7.0.

=== 2.7.0 / 11 Sep 2013

* Fix for 'Could not parse PKey: no start line' error on private keys with
  passphrases (issue #101) [metametaclass]
* Automatically forward environment variables defined in OpenSSH config files
  [fnordfish]
* Guard against socket.gets being nil in Net::SSH::Proxy::HTTP [krishicks]
* Implemented experimental keepalive feature [noric]

=== 2.6.8 / 6 Jul 2013

* Added support for host wildcard substitution [GabKlein]
* Added a wait to the loop in close to help fix possible blocks [Josh
  Kalderimis]
* Fixed test file encoding issues with Ruby 2.0 (#87) [voxik]