[Stateless SG] Test fragmented traffic is allowed by stateless SG

This patch adds scenario test to ensure that fragmented traffic can be
send properly between VMs which are using stateless SG.
There is no need to add same test for stateful SG as this is already
covered by various tests in neutron_tempest_plugin.scenario.test_mtu
module.

Change-Id: Id07a2bee283c33aeb083e68599faecec467a9844
1 file changed