[image-guide] Update the link to VDDK
[image-guide] Update the link to VDDK

Change-Id: I6695b46762fba852f00a9f884a217cd7984a4e08
Implements: blueprint image-guide-rst

AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals