[doxygen] add correct patch

[Than Ngo]

commit 869510229e11d7dc4903a671fed9b1bc7d7ddeeb
Author: Than Ngo <than at redhat.com>
Date:   Wed Jun 6 12:51:26 2012 +0200

    add  correct patch

 doxygen.spec |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/doxygen.spec b/doxygen.spec
index 174276a..42a742d 100644
--- a/doxygen.spec
+++ b/doxygen.spec
@@ -13,7 +13,7 @@ Source0: ftp://ftp.stack.nl/pub/users/dimitri/%{name}-%{version}.src.tar.gz
 Source1: doxywizard.png
 Source2: doxywizard.desktop
 
-Patch1: doxygen-1.7.1-config.patch
+Patch1: doxygen-1.8.1-config.patch
 Patch2: doxygen-1.7.5-timestamp.patch
 
 BuildRequires: perl