VMWARE-STSD service not starting due to empty /usr/lib/vmware-sso/vmware-sts/conf/server.xml file
Resolution
From another installed and working vCenter, running the same version, copy the /usr/lib/vmware-sso/vmware-sts/conf/server.xml file from the working vCenter and replace the empty file with the new one.
Use a scp client like winscp to download the good file and upload it to the non functioning vCenter.
Then stop and start all the vCenter services from vCenter ssh :
Run the following command : service-control --stop --all && service-control --start --all