Comment 4 for bug 739438

Confirmed. Sorry, seems I didn't test this thoroughly enough.

Simple fix: Remove the warning output from dup_temp.py / to_remote().

Advanced fix (see attachment): Add a move() function to the backend interface, let it default to a call to put() + source_path.delete() (for all backends that cannot do this properly), and override it in the localbackend.

(In hindsight, backend.move() could completely *replace* backend.put(), as currently all uses of put() delete the source file afterwards.)