In the deployment of a Demo environment, I want to be able to use alternative Repositories (GIT repo, Fileserver, Docker repo).
The HEAT template contains already variables for Fileserver and Docker:

nexus_repo: https://nexus.onap.org/content/sites/raw
nexus_docker_repo: nexus3.onap.org:10001

but the GIT Repo (gerrit) is hardcoded in the component install scripts, e.g.:
# Run docker containers
cd /opt
git clone -b $GERRIT_BRANCH --single-branch http://gerrit.onap.org/r/aai/test-config

In order to have full flexibility, also the GIT Repo server should be configurable in the onap_openstack.env