raco setup: make "nothing to do" count as success

racket/collects/setup/setup-core.rkt

@@ -589,7 +589,7 @@
                nothing-else-to-do?
                (not (make-tidy)))
       (setup-printf #f "nothing to do")
-      (exit 1))
+      (exit 0))
     (define (cc->name cc)
       (string-join (map path->string (cc-collection cc)) "/"))
     (define (cc->cc+name+id cc)