Closes-Bug: #1401173

Issue is it's failing while parsing virtual_network under interface_list
in instance UVE which doesn't exist in this case
Added the null to parse virtual network only if it exists

Conflicts:
	webroot/monitor/tenant-network/common/ui/js/tenant_monitor_utils.js

Change-Id: Ibee1fdcdac3b14eef2a19676e75afd7cf02ee7a7
Merge "Closes-Bug: #1401173"