Fix to avoid redeclaring the same XSLT variable twice, which cause

runtime errror. Thanks to Reece Dunn for solving this.


[SVN r22518]

tools/boostbook

@@ -1 +1 @@
-Subproject commit 9e75aa444012b345adfe674c213c38628ddf4108
+Subproject commit d001f99756dd242bf8680cf4d52479e63f56294f