Fixes the cli tests after the updates to manifests module.

`install_cert_on_server` functionality is now moved to,
automation-tools github repo.

Also we can now call `clone` function without any arguments,
which picks the default values from the robottelo.properties
file.
Merge pull request #1363 from kbidarkar/fix-cli-manifests

Fixes the cli tests after the updates to manifests module.