Merge pull request #72 from JHaals/master

rescue and retry ssh on AuthenticationFailed
Release 2.7.1

Signed-off-by: Ken Barber <ken@bob.sh>
Merge branch 'release_271'

* release_271:
  Release 2.7.1
rescue and retry ssh on SocketError and Net::SSH::Exception

prevent rspec-system from failing when SSH server is slow starting