automated system tests failing for both default impl and legacy impl

this is an umbrella bug to track the fact that system test (aka. CSIT) is
failing and may be for multiple reasons. When all system tests are passing 100%
we can close this bug, or when we have more specific detailed bugs to assign for
every failure we can close this bug.

here are the jobs for the default implementation:

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-vpnservice-csit-1node-openstack-liberty-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-vpnservice-csit-1node-openstack-mitaka-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-vpnservice-csit-3node-openstack-liberty-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-vpnservice-csit-3node-openstack-mitaka-openstack-boron/

here are the jobs for the legacy implementation:

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-1node-openstack-basic-all-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-1node-openstack-liberty-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-1node-openstack-mitaka-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-3node-clustering-only-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-3node-openstack-liberty-openstack-boron/

https://jenkins.opendaylight.org/releng/view/netvirt/job/netvirt-csit-3node-openstack-mitaka-openstack-boron/