Congratulations on your VCAP5-DCA! I am working on VCP myself.
Are you sure though re: vmware-fdm? I checked a vanilla ESXi 5.1 install I did on a machine that's not part of any cluster and didn't see it in the VIB list:
# esxcli software vib list
# esxcli software vib list | grep fdm
# cat /var/log/fdm.log
I do see an fdm.log file, but it's contents are empty (as shown in the snapshot above.) Since FDM is specific to vCenter, and not all customers have vCenter (or a version that is licensed for HA) and since the version of FDM would be tied to the version of vCenter, it makes sense to me that an ESXi host will either get it when joining vCenter (and more specifically an HA-enabled cluster) or via the HA depot I mentioned, which vCenter 5.1 is still hosting.
