re-add parenthesis and re-balance rails-to-caveman.asd.

I did not notice I added a comment at the end of the ':depends' on
section which cause the closing parenthesis to become part of the
comment. When I have tried to load the system (using ASDF), it was
throwing errors because of this. I though I fix it in the previous
commit but I just created a mess so good it fixed the problem -- at a
basic functioning level. I do not know how the system was loading with
the .asd in its previous state but it did. Anyway, here we
are. '(asdf:load-system :rails-to-caveman)' should run on repeat
now and not produce any errors...

rails-to-caveman.asd

@@ -20,6 +20,7 @@
                "datafly"
                "sxql"
 	       "mito" ; <--- Added in Chapter 4.
+	       )
   :components ((:module "src"
                 :components
                 ((:file "main" :depends-on ("config" "view" "db"))
@@ -29,4 +30,4 @@
 		 (:file "model" :depends-on ("db")) ; <--- Chapter 4.
                  (:file "config"))))
   :description ""
-  :in-order-to ((test-op (test-op "rails-to-caveman-test")))))
+  :in-order-to ((test-op (test-op "rails-to-caveman-test"))))