The RenameFile method renames an existing file on the
remote host to the new name.
Note that you must have permission to change the file name or an
error will occur.
The OldFileName argument specifies the current name of
the file on the remote host.
The NewFileName argument specifies the name that the
existing file will be changed to.
A value of zero is returned if the operation was successful,
otherwise a non-zero error code is returned which indicates the
cause of the failure.