Fix network-isolation.j2.yaml to ignore VIPs for disabled networks
Fix network-isolation.j2.yaml to ignore VIPs for disabled networks

This change modifies network-isolation.j2.yaml to ignore VIPs for
networks that are disabled. This fixes a bug where VIPs would be
created in network-isolation.yaml even if a network was disabled.

Change-Id: I331b8fec3847bce6ca6c22a9f173055121ef65c9

openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates