[hotfix] Staging launch requires valid NRP_VARIABLES_PATH file.

This patch changes the Lugano launch configuration to deploy the
nrp-variables script generated by Puppet to the remote hosts and
properly override NRP_VARIABLES_PATH to ensure Gazebo launch succeeds.

The previous version only set the _VERSION variables, but the file is
required to be accessible for the Gazebo launch to succeed in a staging
environment.

Change-Id: I06ec74420fdd35d3219ee311531aa8d57504936b