`SALClient.copy` does not copy from source

[TOFarmer]

Summary

The SALClient cannot perform the SAL copy operation.

Steps to reproduce

source = '/a/path'
target = '/another/path
sc = SALClient(host)
sc.copy(target, source)

What is the current bug behavior?

The target is copied to itself (i.e. the SAL server is not changed, if the target already exists).

What is the expected correct behavior?

The node at the source path should be copied to the target.

Possible fixes

This is simply because the when the URL is constructed for copying, the target path in both cases.