Remove OVN gap minimum bandwidth support
Remove OVN gap minimum bandwidth support

Since [1], ML2/OVN mechanism driver supports minimum bandwidth
QoS rules. This support was implemented in OVN v22.06.0.

[1]https://review.opendev.org/c/openstack/neutron/+/842292

Related-Bug: #1982951
Change-Id: I52fd399ff9580df3e30d3aa66b3f54882897e6cf

openstack/neutron,mahak/neutron,mahak/neutron,mahak/neutron,openstack/neutron,openstack/neutron