Unskip test_update_port_with_second_ip()

test_update_port_with_second_ip() was skipped because of bug 1364166
which is now in a state which should allow us to unskip it.

Change-Id: I263bd4ef45ea02b18c6d00b6e27f0b12442be9ee
Related-Bug: #1364166
Merge "Unskip test_update_port_with_second_ip()"