FIX: in removeReplica of the LFC, consider that the PFN may have been changed

With the change of endpoint at GRIDKA, it becomes impossible to remove replicas because the LFC uses the SURL for removing a replica. It fails since the SURL has been changed with the new endpoint.
The fix handles this case and gets back the SURL from the LFC. If it is different from the previous one, it tries and remove it...