The initial idea about the avocado.restclient namespace was that
eventually users could write scripts using that as an API to
interact with avocado-server using Python code.

While the idea is still valid, the avocado-server interface is
a simple and standards compliant RESTful interface. Thus, users
can still easily interact with it without us having to support
a formal Python API at this point.

In the future, if need arises, we can improve the Python REST
client API and promote it to a public namespace.
Signed-off-by: NCleber Rosa <crosa@redhat.com>