[libxml2] Fix a Timsort function helper comment

[Daniel Veillard <veillard src gnome org>]

commit 510e7583f4c098858f5a1e7137c51c314d7c66ca
Author: Daniel Veillard <veillard redhat com>
Date:   Tue Sep 4 11:50:36 2012 +0800

    Fix a Timsort function helper comment

 xpath.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/xpath.c b/xpath.c
index 89da0c8..701696e 100644
--- a/xpath.c
+++ b/xpath.c
@@ -148,7 +148,8 @@
  *
  * Comparison function for the Timsort implementation
  *
- * Returns -2 or +2 based on the order
+ * Returns -2 in case of error -1 if first point < second point, 0 if
+ *         it's the same node, +1 otherwise
  */
 static
 int wrap_cmp( xmlNodePtr x, xmlNodePtr y );