[yelp-xsl] Fix error in db-chunk from recent change to use selector entities

[Shaun McCance <shaunm src gnome org>]

commit dd2ffed648f3375974f85c3bad480f6ce8f080d2
Author: Shaun McCance <shaunm gnome org>
Date:   Mon Oct 5 09:07:08 2015 -0400

    Fix error in db-chunk from recent change to use selector entities

 xslt/docbook/common/db-chunk.xsl |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/xslt/docbook/common/db-chunk.xsl b/xslt/docbook/common/db-chunk.xsl
index 3f7ea2b..da62a03 100644
--- a/xslt/docbook/common/db-chunk.xsl
+++ b/xslt/docbook/common/db-chunk.xsl
@@ -94,7 +94,7 @@ REMARK: Explain how this works
 -->
 <xsl:template name="db.chunk.depth-in-chunk">
   <xsl:param name="node" select="."/>
-  <xsl:variable name="divs" select="count($node/ancestor-or-self::&db_chunk;)"/>
+  <xsl:variable name="divs" select="count($node/ancestor-or-self::&db_chunks;)"/>
   <xsl:choose>
     <xsl:when test="$divs &lt; ($db.chunk.max_depth + 1)">
       <xsl:value-of select="count($node/ancestor-or-self::*) - $divs"/>