Added the ability to change the segmentation ID of a network
with ports bound to OVS agent. The rules, both in the integration
bridge and the physical bridge, to convert the internal VLAN tag
and the external segmentation ID (external VLAN tag) are deleted
and created again with the new value. The traffic from the tenant
networks will be tagged then with the new segmentation ID.
Added get network details agent RPC call to retrieve the information
of the updated network.
Partial-Bug: #1806052
Change-Id: I69f6f3ef717c3ed40218099b1f389afd3d39bd62