Update PD section to include dhcpv6_pd_agent info
Update PD section to include dhcpv6_pd_agent info

Change-Id: Ief211052773e6c0723624ceb1704aaf5fb8bd5d8

AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,potsmaster/openstack-manuals,kairoaraujo/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,saeki-masaki/openstack-manuals,saeki-masaki/openstack-manuals,openstack/openstack-manuals,Akasurde/openstack-manuals,kairoaraujo/openstack-manuals,potsmaster/openstack-manuals