Add tests of port_id in the attach interfaces nova API

The attach interfaces API of nova does not specify port_id or
fixed_ips in tempests.
So, need to check these behavior in tempests.

This patch include test case of port_id.

Change-Id: I9f69c267fdf63126e93f334c988fda77464ca2b0
Closes-bug: #1525813
1 file changed