gnu: gnome-control-center: Set correct file name for the 'passwd' binary.

* gnu/packages/gnome.scm (gnome-control-center): Substitute correct path to
  passwd.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/gnome.scm

@@ -5881,6 +5881,9 @@ (define-public gnome-control-center
                  (("\"nm-connection-editor")
                   (string-append "\"" nm-applet
                                  "/bin/nm-connection-editor")))
+               (substitute* '("panels/user-accounts/run-passwd.c")
+                 (("/usr/bin/passwd")
+                  "/run/setuid-programs/passwd"))
                #t))))))
     (native-inputs
      `(("glib:bin" ,glib "bin") ; for glib-mkenums, etc.