Use lexical-binding cookie in some trivial files

* mk/org-fixup.el (org-make-org-version): Add lexical-binding cookie
to autogenerated files.
* lisp/org-install.el: Use lexical-binding.

lisp/org-install.el

@@ -1,4 +1,4 @@
-;;; org-install.el --- backward compatibility file for obsolete configuration
+;;; org-install.el --- backward compatibility file for obsolete configuration  -*- lexical-binding: t -*-
 ;;
 ;;; Code:
 ;;

mk/org-fixup.el

@@ -43,7 +43,7 @@ work correctly if this file is not present (except directly from
 the Git work tree)."
   (with-temp-buffer
     (insert "\
-;;; org-version.el --- autogenerated file, do not edit
+;;; org-version.el --- autogenerated file, do not edit  -*- lexical-binding: t -*-
 ;;
 ;;; Code:
 ;;;\#\#\#autoload