Description of problem:
XSL processing of certain books with publican 1.6.1 breaks. These books build under publican 1.6.0 locally, but when pushed to brew running 1.6.1 they fail, with the error:

runtime error: file file:///usr/share/sgml/docbook/xsl-stylesheets-1.75.1/fo/verbatim.xsl line 439 element param
xsltApplyXSLTTemplate: A potential infinite template recursion was detected.
You can adjust xsltMaxDepth (--maxdepth) in order to raise the maximum number of nested template calls and variables/params (currently set to 250).

Discussions with Rudiger revealed the XSL itself to be the cause of the problem. For an example build, see:

http://brewweb.devel.redhat.com/brew/taskinfo?taskID=2347861

https://brewweb.devel.redhat.com//getfile?taskID=2347862&name=build.log

Version-Release number of selected component (if applicable):
1.6.1 as deployed on brew

How reproducible:
Every time

Steps to Reproduce:
1. Build book locally, succeeds
2. Push to brew, fails