Fix "neutron-mlnx-agent.yaml" to use the new Role ComputeSriovIB
Fix "neutron-mlnx-agent.yaml" to use the new Role ComputeSriovIB

Change-Id: I523743d2b7cbfb906a30c91c232d3bb937907456

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates