CLI update to comply with LFC

The removeFile was returning S_OK({'Successful','Failed'}) and those where never checked
Update DataManagementSystem/Client/FileCatalogClientCLI.py

Add ERROR prefix to make it clearer
fix removeReplica for LFC compliance

Like the removeFile, it needed some support for

#TODO: determine the PFN automatically, why do we need to specify the SE and the PFN to the lfc_unlink call?
Update CLI call to unregister replica

The doc and the call needed to account for the fact that 3 arguments are needed, not 2
Getting replica PFNs

When removing a replica from the LFC, make sure the PFN is supplied
Remove need to specify PFN in removeReplica

Now that the PFN is obtained from the LFC interface, no need to set it here
Merge pull request #1152 from sposs/patch-37

CLI update to comply with LFC