[networking] Adding 'neutron-db-manage revision' command
[networking] Adding 'neutron-db-manage revision' command

Change-Id: I7433860fc22f7eae8e1534a4a283cc5e25a092c6
Closes-bug: 1518422

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals