Tweak which duplicate packages to select

This helps with replacements, as the original package is usually higher up in
the file.

guix-data-service/jobs/load-new-guix-revision.scm

@@ -970,7 +970,7 @@ WHERE job_id = $1")
                        ;; location.
                        (let ((a-location (inferior-package-location a))
                              (b-location (inferior-package-location b)))
-                         (< (location-line a-location)
+                         (> (location-line a-location)
                             (location-line b-location)))
                        (string<? a-version
                                  b-version)))