Skip functional l3 agent test
Skip functional l3 agent test

Since this test merged there have been periodic failures that
seem to be related to SystemExit being raised.  Skipping for now
to give us time to fix.

Change-Id: Ia857835102a9c4c74820cf5eb3c529a3c2fb421e
Related-bug: 1364171

gkotton/vmware-nsx,gkotton/vmware-nsx