Misleading behavior when enabling hardware offloads

[Alin-Gabriel Serdean]

According to the documentation(1) the following setting:
ovs-vsctl set Open_vSwitch . other_config:hw-offload=true|false/unset
should have effects only after vswitchd is restarted.

However, flipping the value on will have the following effect:
Hardware offloads will be enabled for newly created ports,
but not on the ports prior enabling the TC offloads.

If hw-offload got enabled, qdisc configured, hw-offload disabled --> ovs restarted.
This sequence might not delete the qdisc, and vswitchd on restart might not touch existing ones.
As a side effect you will have to delete them manually.

(1) https://github.com/openvswitch/ovs/blob/v2.16.1/vswitchd/vswitch.xml#L225-L248