tests: Update ovn localnet test case.

tests: Update ovn localnet test case.

The OVN localnet port test case did not cover having 2 ports on the same
network and on the same hypervisor.  It also turns out that this case is
broken.  Update the test case to demonstrate the problem.  A solution
should be able to uncomment these additional test_packet lines and have
the test case still pass.

Reported-at: http://openvswitch.org/pipermail/dev/2016-January/064413.html
Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Han Zhou <zhouhan@gmail.com>