This new function in neutron.agent.linux.tc_lib creates a TC filter in
a device depending on the VXLAN ID (VNI) and the source MAC address
(usually the VM TAP MAC address). This filter will send all the egress
tunneled traffic from the VM to a TC class in other to shape it (QoS).
Change-Id: Ic04b52bc0aca7a18fa06ea89e981c80d67f42eb1
Related-Bug: #1560963