[Bugfix] Fixed typo in rfb/util.cxx (caused in r2890)

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@2916 3789f03b-4d11-0410-bbf8-ca57d06f2519

common/rfb/util.cxx

@@ -30,7 +30,7 @@
  * is provided ``as is'' without express or implied warranty.
  */
 
-#ifndef HAVE_COMMON_CONFIG_H
+#ifdef HAVE_COMMON_CONFIG_H
 #include <common-config.h>
 #endif