Remote file copy should not check DZ list and could use ftslave

A remote copy between thor clusters can often report a comment in the logs:

No matching drop zone path to file path: ...

Drop zones are not being used for this remote copy so it can be confusing.
And also there is this msg:

Unable to find machine for 1.2.3.4
Use pull operation because 1.2.3.4 doesn't appear to have an ftslave

But there is an ftslave present, it is just that machine 1.2.3.4 is not in the DZ list so it fails the check for an ftslave.