patch: fix wrong-type-argument error in vc-registered

[Yoichi NAKAYAMA]

The change
2004-09-12  Stefan Monnier  <address@hidden>

        * vc-hooks.el (vc-ignore-dir-regexp): New var.

overlooked that (file-name-directory file) may return nil.
Following is the patch against it.

Regards,
-- 
Yoichi NAKAYAMA

Index: vc-hooks.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/vc-hooks.el,v
retrieving revision 1.169
diff -u -r1.169 vc-hooks.el
--- vc-hooks.el 13 Sep 2004 03:36:11 -0000      1.169
+++ vc-hooks.el 12 Oct 2004 14:38:39 -0000
@@ -336,7 +336,9 @@
 backend is tried first."
   (let (handler)
     (cond
-     ((string-match vc-ignore-dir-regexp (file-name-directory file)) nil)
+     ((and (file-name-directory file)
+          (string-match vc-ignore-dir-regexp (file-name-directory file)))
+      nil)
      ((and (boundp 'file-name-handler-alist)
           (setq handler (find-file-name-handler file 'vc-registered)))
       ;; handler should set vc-backend and return t if registered