installer: Adapt to Guile-newt revision 2.

* gnu/installer/newt/page.scm (run-input-page): Remove component argument that
  is not longer passed to the procedure passed to 'add-component-callback',
 (run-listbox-selection-page): ditto.
 * gnu/installer/newt/user.scm (run-user-add-page): Ditto,
 (run-user-add-page): ditto.

gnu/installer/newt/page.scm

@@ -231,7 +231,7 @@ input box, such as FLAG-PASSWORD."
 
     (add-component-callback
      input-visible-cb
-     (lambda (component)
+     (lambda ()
        (set-entry-flags input-entry
                         FLAG-PASSWORD
                         FLAG-ROLE-TOGGLE)))
@@ -486,7 +486,7 @@ the current listbox item has to be selected by key."
       ;; do nothing.
       (add-component-callback
        listbox
-       (lambda (component)
+       (lambda ()
          (let* ((current-key (current-listbox-entry listbox))
                 (listbox-keys (map car keys))
                 (last-key (last-listbox-key))

gnu/installer/newt/user.scm

@@ -89,7 +89,7 @@ REAL-NAME, and HOME-DIRECTORY as the initial values in the form."
 
     (add-component-callback
      entry-name
-     (lambda (component)
+     (lambda ()
        (set-entry-text entry-home-directory
                        (string-append "/home/" (entry-value entry-name)))
 
@@ -99,7 +99,7 @@ REAL-NAME, and HOME-DIRECTORY as the initial values in the form."
 
     (add-component-callback
      password-visible-cb
-     (lambda (component)
+     (lambda ()
        (set-entry-flags entry-password
                         FLAG-PASSWORD
                         FLAG-ROLE-TOGGLE)))