[xacml] AA43: use "xs:" or "xsi:"?

In some places we use "xsi:<some datatype>", while in other
places we use "xs:<some datatype>".  We should pick one.  I
propose "xs:" just because it is shorter.

Anne
-- 
Anne H. Anderson             Email: 
Sun Microsystems Laboratories
1 Network Drive,UBUR02-311     Tel: 781/442-0928
Burlington, MA 01803-0902 USA  Fax: 781/442-1692