Extend tests and checks for node VIFs

Add more checks to the test_vifs test:
  - check that attached VIF appears in port internal_info;
  - check that VIF was detached and does not appear in
    node's VIF list anymore.
Add test for VIF attachement to node with portgroup.

Partial-Bug: #1666534
Change-Id: I755df18e03d01fe93f85df114b979ea7ea70ca53
1 file changed