gplazma-xacml: remove dependency on org.apache.xalan

There is a xalan implementation which ships with Java.  This dependency does not seem necessary.

We now have all saxon jars in a saxon subdirectory, and no other XSLT libraries on the classpath.

Side benefit is that we can use datanucleus-xml 3.2.1 (without the fix I provided) if needed.

Target: master
Request: 2.8
Request: 2.7
Request: 2.6
Patch: http://rb.dcache.org/r/6582/
Require-book: no
Require-notes: no
Acked-by: Tigran