gexp: Fix argument ordering in 'local-file' macro.

Fixes a regression introduced in
f43ffee908.
Reported by jonsger on #guix.

* guix/gexp.scm (local-file): In the non-literal case, add #:literal?
and #:location after REST.

guix/gexp.scm

@@ -454,9 +454,9 @@ (define-syntax local-file
        (with-syntax ((location (datum->syntax s (syntax-source s))))
         #`(%local-file file
                        (delay (absolute-file-name file (getcwd)))
+                       rest ...
                        #:location 'location
-                       #:literal? #f
-                       rest ...)))
+                       #:literal? #f)))
       ((_)
        #'(syntax-error "missing file name"))
       (id