Fix a few visual issues on the network topology diagram.

This commit separates CIDR labels with a comma and adjusts the vertical
positioning of port labels for improved readability.

Change-Id: I57510033fcc309b5d570d7ee6a9369a97775719b
Fixes: bug #1199086
Merge branch 'stable/grizzly' of https://github.com/openstack/horizon into grizzly/router_rules