gnu: shadow: Remove input labels.

* gnu/packages/admin.scm (shadow)[arguments]: In ‘set-runtime-shell’,
use ‘search-input-file’.
[inputs]: Remove labels.

Change-Id: I1ce9d93f425c77f901d8e21b37d1a069824cab45

gnu/packages/admin.scm

@@ -1052,9 +1052,7 @@ hostname.")
          ,@(if (%current-target-system)
                '((add-before 'configure 'set-runtime-shell
                    (lambda* (#:key inputs #:allow-other-keys)
-                     (let ((shell (string-append
-                                   (assoc-ref inputs "bash")
-                                   "/bin/bash")))
+                     (let ((shell (search-input-file inputs "/bin/bash")))
                        (setenv "RUNTIME_SHELL" shell)
                        (substitute* "configure.ac"
                          (("\\$SHELL")
@@ -1085,12 +1083,12 @@ hostname.")
                (delete-file (string-append bin "/groups"))
                (for-each delete-file (find-files man "^groups\\."))))))))
     (inputs
-     `(,@(if (target-hurd?)
-           '()
-           `(("linux-pam" ,linux-pam)))
-       ,@(if (%current-target-system)
-             `(("bash" ,bash-minimal))
-             '())))
+     (append (if (target-hurd?)
+                 '()
+                 (list linux-pam))
+             (if (%current-target-system)
+                 (list bash-minimal)
+                 '())))
     (home-page "https://github.com/shadow-maint/shadow")
     (synopsis "Authentication-related tools such as passwd, su, and login")
     (description