[libxslt] Add comment about known-to-fail test

[Nick Wellnhofer <nwellnhof src gnome org>]

commit c026a0bb355eb31d0d8caf18b96a5644c796eb33
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Dec 20 17:48:58 2013 +0100

    Add comment about known-to-fail test
    
    tests/general/bug-182.xsl requires a recent version of libxml2.

 tests/general/bug-182.xsl |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/tests/general/bug-182.xsl b/tests/general/bug-182.xsl
index ecce187..cebf2ea 100644
--- a/tests/general/bug-182.xsl
+++ b/tests/general/bug-182.xsl
@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="UTF-8" ?>
 <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>
 
+<!-- Known to fail with libxml2 2.9.0 and 2.9.1. -->
+
 <xsl:template match="node()"/>
 
 <xsl:template match="text()[2]">