Test SF and roles version with serverspec

In order to add another tests validate a
Software Factory upgrade this patch add serverspec
tests to check SF and SF roles version.

- Remove the generate_serverspec that is useless and
  was unused yet.
- hosts.yaml is already provisonned on the install-server-vm image.
- Add hostname in the know_hosts
- Add a serverspec test to validate "edeploy version" output
- Add a serverspec test to validate we retrieve SF version
  in the top menu title.

Change-Id: I7c779f362baa9e3b9d5dd2f8daceea2a78c2f817