refresh: Make 'list-dependents' a monadic procedure.

* guix/scripts/refresh.scm (list-dependents): Remove use of 'with-store'
and 'run-with-store'.
(guix-refresh): Wrap body in with-store/run-with-store.

guix/scripts/refresh.scm

@@ -258,8 +258,6 @@ downloaded and authenticated; not updating~%")
 
 (define (list-dependents packages)
   "List all the things that would need to be rebuilt if PACKAGES are changed."
-  (with-store store
-    (run-with-store store
   ;; Using %BAG-NODE-TYPE is more accurate than using %PACKAGE-NODE-TYPE
   ;; because it includes implicit dependencies.
   (mlet %store-monad ((edges (node-back-edges %bag-node-type
@@ -289,7 +287,7 @@ dependent packages are rebuilt: ~{~a~^ ~}~%"
                      (length covering))
                  (length covering) (length dependents)
                  (map package-full-name covering))))
-          (return #t))))))
+      (return #t))))
 
 
 ;;;
@@ -381,11 +379,12 @@ update would trigger a complete rebuild."
             (some                                 ; user-specified packages
              some))))
     (with-error-handling
+      (with-store store
+        (run-with-store store
           (cond
            (list-dependent?
             (list-dependents packages))
            (update?
-        (let ((store (open-connection)))
             (parameterize ((%openpgp-key-server
                             (or (assoc-ref opts 'key-server)
                                 (%openpgp-key-server)))
@@ -395,7 +394,9 @@ update would trigger a complete rebuild."
               (for-each
                (cut update-package store <> updaters
                     #:key-download key-download)
-             packages))))
+               packages)
+              (with-monad %store-monad
+                (return #t))))
            (else
             (for-each (lambda (package)
                         (match (package-update-path package updaters)
@@ -408,4 +409,6 @@ update would trigger a complete rebuild."
                                      (package-name package) (package-version package)
                                      (upstream-source-version source))))
                           (#f #f)))
-                  packages))))))
+                      packages)
+            (with-monad %store-monad
+              (return #t)))))))))